Language layers refactored; User implements adding & removing Languages; Migrations added

32 files changed, 892 insertions, 257 deletions

diff --git a/src/DevHive.Data/Migrations/20210112111416_User_Implements_Languages.Designer.cs b/src/DevHive.Data/Migrations/20210112111416_User_Implements_Languages.Designer.cs
new file mode 100644
index 0000000..0f1aa80
--- /dev/null
+++ b/src/DevHive.Data/Migrations/20210112111416_User_Implements_Languages.Designer.cs
@@ -0,0 +1,405 @@
+// <auto-generated />
+using System;
+using DevHive.Data;
+using Microsoft.EntityFrameworkCore;
+using Microsoft.EntityFrameworkCore.Infrastructure;
+using Microsoft.EntityFrameworkCore.Migrations;
+using Microsoft.EntityFrameworkCore.Storage.ValueConversion;
+using Npgsql.EntityFrameworkCore.PostgreSQL.Metadata;
+
+namespace DevHive.Data.Migrations
+{
+    [DbContext(typeof(DevHiveContext))]
+    [Migration("20210112111416_User_Implements_Languages")]
+    partial class User_Implements_Languages
+    {
+        protected override void BuildTargetModel(ModelBuilder modelBuilder)
+        {
+#pragma warning disable 612, 618
+            modelBuilder
+                .UseIdentityByDefaultColumns()
+                .HasAnnotation("Relational:MaxIdentifierLength", 63)
+                .HasAnnotation("ProductVersion", "5.0.1");
+
+            modelBuilder.Entity("DevHive.Data.Models.Comment", b =>
+                {
+                    b.Property<Guid>("Id")
+                        .ValueGeneratedOnAdd()
+                        .HasColumnType("uuid");
+
+                    b.Property<Guid>("IssuerId")
+                        .HasColumnType("uuid");
+
+                    b.Property<string>("Message")
+                        .HasColumnType("text");
+
+                    b.Property<DateTime>("TimeCreated")
+                        .HasColumnType("timestamp without time zone");
+
+                    b.HasKey("Id");
+
+                    b.ToTable("Comments");
+                });
+
+            modelBuilder.Entity("DevHive.Data.Models.Language", b =>
+                {
+                    b.Property<Guid>("Id")
+                        .ValueGeneratedOnAdd()
+                        .HasColumnType("uuid");
+
+                    b.Property<string>("Name")
+                        .HasColumnType("text");
+
+                    b.Property<Guid?>("UserId")
+                        .HasColumnType("uuid");
+
+                    b.HasKey("Id");
+
+                    b.HasIndex("UserId");
+
+                    b.ToTable("Languages");
+                });
+
+            modelBuilder.Entity("DevHive.Data.Models.Role", b =>
+                {
+                    b.Property<Guid>("Id")
+                        .ValueGeneratedOnAdd()
+                        .HasColumnType("uuid");
+
+                    b.Property<string>("ConcurrencyStamp")
+                        .IsConcurrencyToken()
+                        .HasColumnType("text");
+
+                    b.Property<string>("Name")
+                        .HasMaxLength(256)
+                        .HasColumnType("character varying(256)");
+
+                    b.Property<string>("NormalizedName")
+                        .HasMaxLength(256)
+                        .HasColumnType("character varying(256)");
+
+                    b.HasKey("Id");
+
+                    b.HasIndex("NormalizedName")
+                        .IsUnique()
+                        .HasDatabaseName("RoleNameIndex");
+
+                    b.ToTable("AspNetRoles");
+                });
+
+            modelBuilder.Entity("DevHive.Data.Models.Technology", b =>
+                {
+                    b.Property<Guid>("Id")
+                        .ValueGeneratedOnAdd()
+                        .HasColumnType("uuid");
+
+                    b.Property<string>("Name")
+                        .HasColumnType("text");
+
+                    b.Property<Guid?>("UserId")
+                        .HasColumnType("uuid");
+
+                    b.HasKey("Id");
+
+                    b.HasIndex("UserId");
+
+                    b.ToTable("Technologies");
+                });
+
+            modelBuilder.Entity("DevHive.Data.Models.User", b =>
+                {
+                    b.Property<Guid>("Id")
+                        .ValueGeneratedOnAdd()
+                        .HasColumnType("uuid");
+
+                    b.Property<int>("AccessFailedCount")
+                        .HasColumnType("integer");
+
+                    b.Property<string>("ConcurrencyStamp")
+                        .IsConcurrencyToken()
+                        .HasColumnType("text");
+
+                    b.Property<string>("Email")
+                        .HasMaxLength(256)
+                        .HasColumnType("character varying(256)");
+
+                    b.Property<bool>("EmailConfirmed")
+                        .HasColumnType("boolean");
+
+                    b.Property<string>("FirstName")
+                        .HasColumnType("text");
+
+                    b.Property<string>("LastName")
+                        .HasColumnType("text");
+
+                    b.Property<bool>("LockoutEnabled")
+                        .HasColumnType("boolean");
+
+                    b.Property<DateTimeOffset?>("LockoutEnd")
+                        .HasColumnType("timestamp with time zone");
+
+                    b.Property<string>("NormalizedEmail")
+                        .HasMaxLength(256)
+                        .HasColumnType("character varying(256)");
+
+                    b.Property<string>("NormalizedUserName")
+                        .HasMaxLength(256)
+                        .HasColumnType("character varying(256)");
+
+                    b.Property<string>("PasswordHash")
+                        .HasColumnType("text");
+
+                    b.Property<string>("PhoneNumber")
+                        .HasColumnType("text");
+
+                    b.Property<bool>("PhoneNumberConfirmed")
+                        .HasColumnType("boolean");
+
+                    b.Property<string>("ProfilePictureUrl")
+                        .HasColumnType("text");
+
+                    b.Property<string>("SecurityStamp")
+                        .HasColumnType("text");
+
+                    b.Property<bool>("TwoFactorEnabled")
+                        .HasColumnType("boolean");
+
+                    b.Property<Guid?>("UserId")
+                        .HasColumnType("uuid");
+
+                    b.Property<string>("UserName")
+                        .HasMaxLength(256)
+                        .HasColumnType("character varying(256)");
+
+                    b.HasKey("Id");
+
+                    b.HasIndex("NormalizedEmail")
+                        .HasDatabaseName("EmailIndex");
+
+                    b.HasIndex("NormalizedUserName")
+                        .IsUnique()
+                        .HasDatabaseName("UserNameIndex");
+
+                    b.HasIndex("UserId");
+
+                    b.HasIndex("UserName")
+                        .IsUnique();
+
+                    b.ToTable("AspNetUsers");
+                });
+
+            modelBuilder.Entity("Microsoft.AspNetCore.Identity.IdentityRoleClaim<System.Guid>", b =>
+                {
+                    b.Property<int>("Id")
+                        .ValueGeneratedOnAdd()
+                        .HasColumnType("integer")
+                        .UseIdentityByDefaultColumn();
+
+                    b.Property<string>("ClaimType")
+                        .HasColumnType("text");
+
+                    b.Property<string>("ClaimValue")
+                        .HasColumnType("text");
+
+                    b.Property<Guid>("RoleId")
+                        .HasColumnType("uuid");
+
+                    b.HasKey("Id");
+
+                    b.HasIndex("RoleId");
+
+                    b.ToTable("AspNetRoleClaims");
+                });
+
+            modelBuilder.Entity("Microsoft.AspNetCore.Identity.IdentityUserClaim<System.Guid>", b =>
+                {
+                    b.Property<int>("Id")
+                        .ValueGeneratedOnAdd()
+                        .HasColumnType("integer")
+                        .UseIdentityByDefaultColumn();
+
+                    b.Property<string>("ClaimType")
+                        .HasColumnType("text");
+
+                    b.Property<string>("ClaimValue")
+                        .HasColumnType("text");
+
+                    b.Property<Guid>("UserId")
+                        .HasColumnType("uuid");
+
+                    b.HasKey("Id");
+
+                    b.HasIndex("UserId");
+
+                    b.ToTable("AspNetUserClaims");
+                });
+
+            modelBuilder.Entity("Microsoft.AspNetCore.Identity.IdentityUserLogin<System.Guid>", b =>
+                {
+                    b.Property<string>("LoginProvider")
+                        .HasColumnType("text");
+
+                    b.Property<string>("ProviderKey")
+                        .HasColumnType("text");
+
+                    b.Property<string>("ProviderDisplayName")
+                        .HasColumnType("text");
+
+                    b.Property<Guid>("UserId")
+                        .HasColumnType("uuid");
+
+                    b.HasKey("LoginProvider", "ProviderKey");
+
+                    b.HasIndex("UserId");
+
+                    b.ToTable("AspNetUserLogins");
+                });
+
+            modelBuilder.Entity("Microsoft.AspNetCore.Identity.IdentityUserRole<System.Guid>", b =>
+                {
+                    b.Property<Guid>("UserId")
+                        .HasColumnType("uuid");
+
+                    b.Property<Guid>("RoleId")
+                        .HasColumnType("uuid");
+
+                    b.HasKey("UserId", "RoleId");
+
+                    b.HasIndex("RoleId");
+
+                    b.ToTable("AspNetUserRoles");
+                });
+
+            modelBuilder.Entity("Microsoft.AspNetCore.Identity.IdentityUserToken<System.Guid>", b =>
+                {
+                    b.Property<Guid>("UserId")
+                        .HasColumnType("uuid");
+
+                    b.Property<string>("LoginProvider")
+                        .HasColumnType("text");
+
+                    b.Property<string>("Name")
+                        .HasColumnType("text");
+
+                    b.Property<string>("Value")
+                        .HasColumnType("text");
+
+                    b.HasKey("UserId", "LoginProvider", "Name");
+
+                    b.ToTable("AspNetUserTokens");
+                });
+
+            modelBuilder.Entity("RoleUser", b =>
+                {
+                    b.Property<Guid>("RolesId")
+                        .HasColumnType("uuid");
+
+                    b.Property<Guid>("UsersId")
+                        .HasColumnType("uuid");
+
+                    b.HasKey("RolesId", "UsersId");
+
+                    b.HasIndex("UsersId");
+
+                    b.ToTable("RoleUser");
+                });
+
+            modelBuilder.Entity("DevHive.Data.Models.Language", b =>
+                {
+                    b.HasOne("DevHive.Data.Models.User", null)
+                        .WithMany("Langauges")
+                        .HasForeignKey("UserId");
+                });
+
+            modelBuilder.Entity("DevHive.Data.Models.Technology", b =>
+                {
+                    b.HasOne("DevHive.Data.Models.User", null)
+                        .WithMany("Technologies")
+                        .HasForeignKey("UserId");
+                });
+
+            modelBuilder.Entity("DevHive.Data.Models.User", b =>
+                {
+                    b.HasOne("DevHive.Data.Models.User", null)
+                        .WithMany("Friends")
+                        .HasForeignKey("UserId");
+                });
+
+            modelBuilder.Entity("Microsoft.AspNetCore.Identity.IdentityRoleClaim<System.Guid>", b =>
+                {
+                    b.HasOne("DevHive.Data.Models.Role", null)
+                        .WithMany()
+                        .HasForeignKey("RoleId")
+                        .OnDelete(DeleteBehavior.Cascade)
+                        .IsRequired();
+                });
+
+            modelBuilder.Entity("Microsoft.AspNetCore.Identity.IdentityUserClaim<System.Guid>", b =>
+                {
+                    b.HasOne("DevHive.Data.Models.User", null)
+                        .WithMany()
+                        .HasForeignKey("UserId")
+                        .OnDelete(DeleteBehavior.Cascade)
+                        .IsRequired();
+                });
+
+            modelBuilder.Entity("Microsoft.AspNetCore.Identity.IdentityUserLogin<System.Guid>", b =>
+                {
+                    b.HasOne("DevHive.Data.Models.User", null)
+                        .WithMany()
+                        .HasForeignKey("UserId")
+                        .OnDelete(DeleteBehavior.Cascade)
+                        .IsRequired();
+                });
+
+            modelBuilder.Entity("Microsoft.AspNetCore.Identity.IdentityUserRole<System.Guid>", b =>
+                {
+                    b.HasOne("DevHive.Data.Models.Role", null)
+                        .WithMany()
+                        .HasForeignKey("RoleId")
+                        .OnDelete(DeleteBehavior.Cascade)
+                        .IsRequired();
+
+                    b.HasOne("DevHive.Data.Models.User", null)
+                        .WithMany()
+                        .HasForeignKey("UserId")
+                        .OnDelete(DeleteBehavior.Cascade)
+                        .IsRequired();
+                });
+
+            modelBuilder.Entity("Microsoft.AspNetCore.Identity.IdentityUserToken<System.Guid>", b =>
+                {
+                    b.HasOne("DevHive.Data.Models.User", null)
+                        .WithMany()
+                        .HasForeignKey("UserId")
+                        .OnDelete(DeleteBehavior.Cascade)
+                        .IsRequired();
+                });
+
+            modelBuilder.Entity("RoleUser", b =>
+                {
+                    b.HasOne("DevHive.Data.Models.Role", null)
+                        .WithMany()
+                        .HasForeignKey("RolesId")
+                        .OnDelete(DeleteBehavior.Cascade)
+                        .IsRequired();
+
+                    b.HasOne("DevHive.Data.Models.User", null)
+                        .WithMany()
+                        .HasForeignKey("UsersId")
+                        .OnDelete(DeleteBehavior.Cascade)
+                        .IsRequired();
+                });
+
+            modelBuilder.Entity("DevHive.Data.Models.User", b =>
+                {
+                    b.Navigation("Friends");
+
+                    b.Navigation("Langauges");
+
+                    b.Navigation("Technologies");
+                });
+#pragma warning restore 612, 618
+        }
+    }
+}
diff --git a/src/DevHive.Data/Migrations/20210112111416_User_Implements_Languages.cs b/src/DevHive.Data/Migrations/20210112111416_User_Implements_Languages.cs
new file mode 100644
index 0000000..a51ad09
--- /dev/null
+++ b/src/DevHive.Data/Migrations/20210112111416_User_Implements_Languages.cs
@@ -0,0 +1,106 @@
+using System;
+using Microsoft.EntityFrameworkCore.Migrations;
+
+namespace DevHive.Data.Migrations
+{
+    public partial class User_Implements_Languages : Migration
+    {
+        protected override void Up(MigrationBuilder migrationBuilder)
+        {
+            migrationBuilder.RenameColumn(
+                name: "UserId",
+                table: "Comments",
+                newName: "IssuerId");
+
+            migrationBuilder.RenameColumn(
+                name: "Date",
+                table: "Comments",
+                newName: "TimeCreated");
+
+            migrationBuilder.RenameColumn(
+                name: "ProfilePicture",
+                table: "AspNetUsers",
+                newName: "ProfilePictureUrl");
+
+            migrationBuilder.AddColumn<Guid>(
+                name: "UserId",
+                table: "Technologies",
+                type: "uuid",
+                nullable: true);
+
+            migrationBuilder.AddColumn<Guid>(
+                name: "UserId",
+                table: "Languages",
+                type: "uuid",
+                nullable: true);
+
+            migrationBuilder.CreateIndex(
+                name: "IX_Technologies_UserId",
+                table: "Technologies",
+                column: "UserId");
+
+            migrationBuilder.CreateIndex(
+                name: "IX_Languages_UserId",
+                table: "Languages",
+                column: "UserId");
+
+            migrationBuilder.AddForeignKey(
+                name: "FK_Languages_AspNetUsers_UserId",
+                table: "Languages",
+                column: "UserId",
+                principalTable: "AspNetUsers",
+                principalColumn: "Id",
+                onDelete: ReferentialAction.Restrict);
+
+            migrationBuilder.AddForeignKey(
+                name: "FK_Technologies_AspNetUsers_UserId",
+                table: "Technologies",
+                column: "UserId",
+                principalTable: "AspNetUsers",
+                principalColumn: "Id",
+                onDelete: ReferentialAction.Restrict);
+        }
+
+        protected override void Down(MigrationBuilder migrationBuilder)
+        {
+            migrationBuilder.DropForeignKey(
+                name: "FK_Languages_AspNetUsers_UserId",
+                table: "Languages");
+
+            migrationBuilder.DropForeignKey(
+                name: "FK_Technologies_AspNetUsers_UserId",
+                table: "Technologies");
+
+            migrationBuilder.DropIndex(
+                name: "IX_Technologies_UserId",
+                table: "Technologies");
+
+            migrationBuilder.DropIndex(
+                name: "IX_Languages_UserId",
+                table: "Languages");
+
+            migrationBuilder.DropColumn(
+                name: "UserId",
+                table: "Technologies");
+
+            migrationBuilder.DropColumn(
+                name: "UserId",
+                table: "Languages");
+
+            migrationBuilder.RenameColumn(
+                name: "TimeCreated",
+                table: "Comments",
+                newName: "Date");
+
+            migrationBuilder.RenameColumn(
+                name: "IssuerId",
+                table: "Comments",
+                newName: "UserId");
+
+            migrationBuilder.RenameColumn(
+                name: "ProfilePictureUrl",
+                table: "AspNetUsers",
+                newName: "ProfilePicture");
+        }
+    }
+}
diff --git a/src/DevHive.Data/Migrations/DevHiveContextModelSnapshot.cs b/src/DevHive.Data/Migrations/DevHiveContextModelSnapshot.cs
index c7ff6c6..cc6d24d 100644
--- a/src/DevHive.Data/Migrations/DevHiveContextModelSnapshot.cs
+++ b/src/DevHive.Data/Migrations/DevHiveContextModelSnapshot.cs
@@ -25,14 +25,14 @@ namespace DevHive.Data.Migrations
                         .ValueGeneratedOnAdd()
                         .HasColumnType("uuid");
 
-                    b.Property<DateTime>("Date")
-                        .HasColumnType("timestamp without time zone");
+                    b.Property<Guid>("IssuerId")
+                        .HasColumnType("uuid");
 
                     b.Property<string>("Message")
                         .HasColumnType("text");
 
-                    b.Property<Guid>("UserId")
-                        .HasColumnType("uuid");
+                    b.Property<DateTime>("TimeCreated")
+                        .HasColumnType("timestamp without time zone");
 
                     b.HasKey("Id");
 
@@ -48,8 +48,13 @@ namespace DevHive.Data.Migrations
                     b.Property<string>("Name")
                         .HasColumnType("text");
 
+                    b.Property<Guid?>("UserId")
+                        .HasColumnType("uuid");
+
                     b.HasKey("Id");
 
+                    b.HasIndex("UserId");
+
                     b.ToTable("Languages");
                 });
 
@@ -89,8 +94,13 @@ namespace DevHive.Data.Migrations
                     b.Property<string>("Name")
                         .HasColumnType("text");
 
+                    b.Property<Guid?>("UserId")
+                        .HasColumnType("uuid");
+
                     b.HasKey("Id");
 
+                    b.HasIndex("UserId");
+
                     b.ToTable("Technologies");
                 });
 
@@ -143,7 +153,7 @@ namespace DevHive.Data.Migrations
                     b.Property<bool>("PhoneNumberConfirmed")
                         .HasColumnType("boolean");
 
-                    b.Property<string>("ProfilePicture")
+                    b.Property<string>("ProfilePictureUrl")
                         .HasColumnType("text");
 
                     b.Property<string>("SecurityStamp")
@@ -292,6 +302,20 @@ namespace DevHive.Data.Migrations
                     b.ToTable("RoleUser");
                 });
 
+            modelBuilder.Entity("DevHive.Data.Models.Language", b =>
+                {
+                    b.HasOne("DevHive.Data.Models.User", null)
+                        .WithMany("Langauges")
+                        .HasForeignKey("UserId");
+                });
+
+            modelBuilder.Entity("DevHive.Data.Models.Technology", b =>
+                {
+                    b.HasOne("DevHive.Data.Models.User", null)
+                        .WithMany("Technologies")
+                        .HasForeignKey("UserId");
+                });
+
             modelBuilder.Entity("DevHive.Data.Models.User", b =>
                 {
                     b.HasOne("DevHive.Data.Models.User", null)
@@ -368,6 +392,10 @@ namespace DevHive.Data.Migrations
             modelBuilder.Entity("DevHive.Data.Models.User", b =>
                 {
                     b.Navigation("Friends");
+
+                    b.Navigation("Langauges");
+
+                    b.Navigation("Technologies");
                 });
 #pragma warning restore 612, 618
         }
diff --git a/src/DevHive.Data/Models/Technology.cs b/src/DevHive.Data/Models/Technology.cs
index 2e0aeed..a462d20 100644
--- a/src/DevHive.Data/Models/Technology.cs
+++ b/src/DevHive.Data/Models/Technology.cs
@@ -5,7 +5,6 @@ namespace DevHive.Data.Models
 	public class Technology : IModel
 	{
 		public Guid Id { get; set; }
-
 		public string Name { get; set; }
 	}
 }
diff --git a/src/DevHive.Data/Models/User.cs b/src/DevHive.Data/Models/User.cs
index eef0af2..fda4651 100644
--- a/src/DevHive.Data/Models/User.cs
+++ b/src/DevHive.Data/Models/User.cs
@@ -12,7 +12,17 @@ namespace DevHive.Data.Models
 
 		public string LastName { get; set; }
 
-		public string ProfilePicture { get; set; }
+		public string ProfilePictureUrl { get; set; }
+
+		/// <summary>
+		/// Languages that the user uses or is familiar with
+		/// </summary>
+		public IList<Language> Langauges { get; set; }
+
+		/// <summary>
+		/// Technologies that the user uses or is familiar with
+		/// </summary>
+		public IList<Technology> Technologies { get; set; }
 
 		public virtual IList<Role> Roles { get; set; } = new List<Role>();
 
diff --git a/src/DevHive.Data/Repositories/Contracts/ILanguageRepository.cs b/src/DevHive.Data/Repositories/Contracts/ILanguageRepository.cs
deleted file mode 100644
index e44d27b..0000000
--- a/src/DevHive.Data/Repositories/Contracts/ILanguageRepository.cs
+++ /dev/null
@@ -1,13 +0,0 @@
-using DevHive.Data.Models;
-using System;
-using System.Threading.Tasks;
-
-namespace DevHive.Data.Repositories.Contracts
-{
-    public interface ILanguageRepository : IRepository<Language>
-    {
-		public Task<bool> DoesLanguageNameExist(string languageName);
-
-		public Task<bool> DoesLanguageExist(Guid id);
-	}
-}
diff --git a/src/DevHive.Data/Repositories/Contracts/IPostRepository.cs b/src/DevHive.Data/Repositories/Contracts/IPostRepository.cs
deleted file mode 100644
index 930138a..0000000
--- a/src/DevHive.Data/Repositories/Contracts/IPostRepository.cs
+++ /dev/null
@@ -1,21 +0,0 @@
-using DevHive.Data.Models;
-using System;
-using System.Threading.Tasks;
-
-namespace DevHive.Data.Repositories.Contracts
-{
-    public interface IPostRepository : IRepository<Post>
-    {
-        public Task<bool> AddCommentAsync(Comment entity);
-
-        public Task<Comment> GetCommentByIdAsync(Guid id);
-
-        public Task<bool> EditCommentAsync(Comment newEntity);
-
-		public Task<bool> DeleteCommentAsync(Comment entity);
-
-		public Task<bool> DoesPostExist(Guid postId);
-
-        public Task<bool> DoesCommentExist(Guid id);
-	}
-}
diff --git a/src/DevHive.Data/Repositories/Contracts/IRoleRepository.cs b/src/DevHive.Data/Repositories/Contracts/IRoleRepository.cs
deleted file mode 100644
index 6cb8a4e..0000000
--- a/src/DevHive.Data/Repositories/Contracts/IRoleRepository.cs
+++ /dev/null
@@ -1,15 +0,0 @@
-using DevHive.Data.Models;
-using System;
-using System.Threading.Tasks;
-
-namespace DevHive.Data.Repositories.Contracts
-{
-    public interface IRoleRepository : IRepository<Role>
-    {
-		public Task<Role> GetByNameAsync(string name);
-
-		public Task<bool> DoesNameExist(string name);
-
-		public Task<bool> DoesRoleExist(Guid id);
-	}
-}
diff --git a/src/DevHive.Data/Repositories/Contracts/ITechnologyRepository.cs b/src/DevHive.Data/Repositories/Contracts/ITechnologyRepository.cs
deleted file mode 100644
index 3c4a6b6..0000000
--- a/src/DevHive.Data/Repositories/Contracts/ITechnologyRepository.cs
+++ /dev/null
@@ -1,13 +0,0 @@
-using DevHive.Data.Models;
-using System;
-using System.Threading.Tasks;
-
-namespace DevHive.Data.Repositories.Contracts
-{
-    public interface ITechnologyRepository : IRepository<Technology>
-    {
-		public Task<bool> DoesTechnologyNameExist(string technologyName);
-
-		public Task<bool> DoesTechnologyExist(Guid id);
-	}
-}
diff --git a/src/DevHive.Data/Repositories/Contracts/IUserRepository.cs b/src/DevHive.Data/Repositories/Contracts/IUserRepository.cs
deleted file mode 100644
index 74c4486..0000000
--- a/src/DevHive.Data/Repositories/Contracts/IUserRepository.cs
+++ /dev/null
@@ -1,26 +0,0 @@
-using DevHive.Data.Models;
-using System;
-using System.Collections.Generic;
-using System.Threading.Tasks;
-
-namespace DevHive.Data.Repositories.Contracts
-{
-    public interface IUserRepository : IRepository<User>
-	{
-		public Task<bool> AddFriendAsync(User user, User friend);
-
-		public IEnumerable<User> QueryAll();
-
-		public Task<User> GetByUsername(string username);
-
-		public Task<bool> RemoveFriendAsync(User user, User friend);
-
-		public bool DoesUserExist(Guid id);
-
-		public bool DoesUserHaveThisUsername(Guid id, string username);
-
-		public Task<bool> DoesUsernameExist(string username);
-
-		public Task<bool> DoesEmailExist(string email);
-	}
-}
diff --git a/src/DevHive.Data/Repositories/Contracts/IRepository.cs b/src/DevHive.Data/Repositories/IRepository.cs
index 37c5170..920ba13 100644
--- a/src/DevHive.Data/Repositories/Contracts/IRepository.cs
+++ b/src/DevHive.Data/Repositories/IRepository.cs
@@ -1,7 +1,7 @@
 using System;
 using System.Threading.Tasks;
 
-namespace DevHive.Data.Repositories.Contracts
+namespace DevHive.Data.Repositories
 {
 	public interface IRepository<TEntity>
 		where TEntity : class
diff --git a/src/DevHive.Data/Repositories/LanguageRepository.cs b/src/DevHive.Data/Repositories/LanguageRepository.cs
index 243192a..5d8217a 100644
--- a/src/DevHive.Data/Repositories/LanguageRepository.cs
+++ b/src/DevHive.Data/Repositories/LanguageRepository.cs
@@ -1,13 +1,13 @@
 using System;
+using System.Linq;
 using System.Threading.Tasks;
 using DevHive.Common.Models.Misc;
 using DevHive.Data.Models;
-using DevHive.Data.Repositories.Contracts;
 using Microsoft.EntityFrameworkCore;
 
 namespace DevHive.Data.Repositories
 {
-	public class LanguageRepository : ILanguageRepository
+	public class LanguageRepository : IRepository<Language>
 	{
 		private readonly DevHiveContext _context;
 
@@ -16,7 +16,8 @@ namespace DevHive.Data.Repositories
 			this._context = context;
 		}
 
-		//Create
+		#region Create
+
 		public async Task<bool> AddAsync(Language entity)
 		{
 			await this._context
@@ -25,42 +26,32 @@ namespace DevHive.Data.Repositories
 
 			return await RepositoryMethods.SaveChangesAsync(this._context);
 		}
+		#endregion
+
+		#region Read
 
-		//Read
 		public async Task<Language> GetByIdAsync(Guid id)
 		{
 			return await this._context
 				.Set<Language>()
 				.FindAsync(id);
 		}
+		#endregion
 
-		public async Task<bool> DoesLanguageNameExist(string languageName)
-		{
-			return await this._context
-				.Set<Language>()
-				.AsNoTracking()
-				.AnyAsync(r => r.Name == languageName);
-		}
-
-		public async Task<bool> DoesLanguageExist(Guid id)
-		{
-			return await this._context
-				.Set<Language>()
-				.AsNoTracking()
-				.AnyAsync(r => r.Id == id);
-		}
+		#region Update
 
-		//Update
 		public async Task<bool> EditAsync(Language newEntity)
 		{
-				this._context
-				.Set<Language>()
-				.Update(newEntity);
+			this._context
+			.Set<Language>()
+			.Update(newEntity);
 
 			return await RepositoryMethods.SaveChangesAsync(this._context);
 		}
+		#endregion
+
+		#region Delete
 
-		//Delete
 		public async Task<bool> DeleteAsync(Language entity)
 		{
 			this._context
@@ -69,5 +60,21 @@ namespace DevHive.Data.Repositories
 
 			return await RepositoryMethods.SaveChangesAsync(this._context);
 		}
+		#endregion
+
+		#region Validations 
+
+		public async Task<bool> DoesLanguageNameExistAsync(string languageName)
+		{
+			return await this._context.Languages
+				.AnyAsync(r => r.Name == languageName);
+		}
+
+		public async Task<bool> DoesLanguageExistAsync(Guid id)
+		{
+			return await this._context.Languages
+				.AnyAsync(r => r.Id == id);
+		}
+		#endregion
 	}
 }
\ No newline at end of file
diff --git a/src/DevHive.Data/Repositories/PostRepository.cs b/src/DevHive.Data/Repositories/PostRepository.cs
index 0acfc23..002fb17 100644
--- a/src/DevHive.Data/Repositories/PostRepository.cs
+++ b/src/DevHive.Data/Repositories/PostRepository.cs
@@ -2,12 +2,11 @@ using System;
 using System.Threading.Tasks;
 using DevHive.Common.Models.Misc;
 using DevHive.Data.Models;
-using DevHive.Data.Repositories.Contracts;
 using Microsoft.EntityFrameworkCore;
 
 namespace DevHive.Data.Repositories
 {
-	public class PostRepository : IPostRepository
+	public class PostRepository : IRepository<Post>
 	{
 		private readonly DevHiveContext _context;
 
@@ -88,6 +87,8 @@ namespace DevHive.Data.Repositories
 			return await RepositoryMethods.SaveChangesAsync(this._context);
 		}
 	
+		#region Validations
+
 		public async Task<bool> DoesPostExist(Guid postId)
 		{
 			return await this._context
@@ -103,5 +104,6 @@ namespace DevHive.Data.Repositories
 				.AsNoTracking()
 				.AnyAsync(r => r.Id == id);
 		}
+		#endregion
 	}
 }
\ No newline at end of file
diff --git a/src/DevHive.Data/Repositories/RoleRepository.cs b/src/DevHive.Data/Repositories/RoleRepository.cs
index d6f83a8..0ca1646 100644
--- a/src/DevHive.Data/Repositories/RoleRepository.cs
+++ b/src/DevHive.Data/Repositories/RoleRepository.cs
@@ -2,12 +2,11 @@ using System;
 using System.Threading.Tasks;
 using DevHive.Common.Models.Misc;
 using DevHive.Data.Models;
-using DevHive.Data.Repositories.Contracts;
 using Microsoft.EntityFrameworkCore;
 
 namespace DevHive.Data.Repositories
 {
-	public class RoleRepository  : IRoleRepository
+	public class RoleRepository  : IRepository<Role>
 	{
 		private readonly DevHiveContext _context;
 
diff --git a/src/DevHive.Data/Repositories/TechnologyRepository.cs b/src/DevHive.Data/Repositories/TechnologyRepository.cs
index 27918ca..2ed3a23 100644
--- a/src/DevHive.Data/Repositories/TechnologyRepository.cs
+++ b/src/DevHive.Data/Repositories/TechnologyRepository.cs
@@ -2,13 +2,12 @@ using System;
 using System.Threading.Tasks;
 using DevHive.Common.Models.Misc;
 using DevHive.Data.Models;
-using DevHive.Data.Repositories.Contracts;
 using Microsoft.EntityFrameworkCore;
 
 
 namespace DevHive.Data.Repositories
 {
-	public abstract class TechnologyRepository : ITechnologyRepository
+	public abstract class TechnologyRepository : IRepository<Technology>
 	{
 		private DevHiveContext _context;
 
@@ -27,7 +26,7 @@ namespace DevHive.Data.Repositories
 			return await RepositoryMethods.SaveChangesAsync(this._context);
 		}
 
-		//Read		
+		//Read
 		public async Task<Technology> GetByIdAsync(Guid id)
 		{
 			return await this._context
diff --git a/src/DevHive.Data/Repositories/UserRepository.cs b/src/DevHive.Data/Repositories/UserRepository.cs
index 5142b82..e3c1304 100644
--- a/src/DevHive.Data/Repositories/UserRepository.cs
+++ b/src/DevHive.Data/Repositories/UserRepository.cs
@@ -4,12 +4,11 @@ using System.Linq;
 using System.Threading.Tasks;
 using DevHive.Common.Models.Misc;
 using DevHive.Data.Models;
-using DevHive.Data.Repositories.Contracts;
 using Microsoft.EntityFrameworkCore;
 
 namespace DevHive.Data.Repositories
 {
-	public class UserRepository : IUserRepository
+	public class UserRepository : IRepository<User>
 	{
 		private readonly DevHiveContext _context;
 
@@ -18,11 +17,11 @@ namespace DevHive.Data.Repositories
 			this._context = context;
 		}
 
-		//Create
+		#region Create
+
 		public async Task<bool> AddAsync(User entity)
 		{
-			await this._context
-				.Set<User>()
+			await this._context.Users
 				.AddAsync(entity);
 
 			return await RepositoryMethods.SaveChangesAsync(this._context);
@@ -35,12 +34,31 @@ namespace DevHive.Data.Repositories
 
 			return await RepositoryMethods.SaveChangesAsync(this._context);
 		}
-		
-		//Read
+
+		public async Task<bool> AddLanguageToUserAsync(User user, Language language)
+		{
+			this._context.Update(user);
+
+			user.Langauges.Add(language);
+
+			return await RepositoryMethods.SaveChangesAsync(this._context);
+		}
+
+		public async Task<bool> AddTechnologyToUserAsync(User user, Technology technology)
+		{
+			this._context.Update(user);
+
+			user.Technologies.Add(technology);
+
+			return await RepositoryMethods.SaveChangesAsync(this._context);
+		}
+		#endregion
+
+		#region Read
+
 		public IEnumerable<User> QueryAll()
 		{
-			return this._context
-				.Set<User>()
+			return this._context.Users
 				.Include(x => x.Roles)
 				.AsNoTracking()
 				.AsEnumerable();
@@ -48,8 +66,7 @@ namespace DevHive.Data.Repositories
 
 		public async Task<User> GetByIdAsync(Guid id)
 		{
-			return await this._context
-				.Set<User>()
+			return await this._context.Users
 				.Include(x => x.Roles)
 				.Include(x => x.Friends)
 				.FirstOrDefaultAsync(x => x.Id == id);
@@ -57,13 +74,36 @@ namespace DevHive.Data.Repositories
 
 		public async Task<User> GetByUsername(string username)
 		{
-			return await this._context
-				.Set<User>()
+			return await this._context.Users
 				.Include(u => u.Roles)
 				.FirstOrDefaultAsync(x => x.UserName == username);
 		}
 
-		//Update
+		public IList<Language> GetUserLanguages(User user)
+		{
+			return user.Langauges;
+		}
+
+		public Language GetUserLanguage(User user, Language language)
+		{
+			return user.Langauges
+				.FirstOrDefault(x => x.Id == language.Id);
+		}
+		
+		public IList<Technology> GetUserTechnologies(User user)
+		{
+			return user.Technologies;
+		}
+
+		public Technology GetUserTechnology(User user, Technology technology)
+		{
+			return user.Technologies
+				.FirstOrDefault(x => x.Id == technology.Id);
+		}
+		#endregion
+
+		#region Update
+
 		public async Task<bool> EditAsync(User newEntity)
 		{
 			User user = await this.GetByIdAsync(newEntity.Id);
@@ -76,11 +116,32 @@ namespace DevHive.Data.Repositories
 			return await RepositoryMethods.SaveChangesAsync(this._context);
 		}
 
-		//Delete
+		public async Task<bool> EditUserLanguage(User user, Language oldLang, Language newLang)
+		{
+			this._context.Update(user);
+
+			user.Langauges.Remove(oldLang);
+			user.Langauges.Add(newLang);
+
+			return await RepositoryMethods.SaveChangesAsync(this._context);
+		}
+
+		public async Task<bool> EditUserTechnologies(User user, Technology oldTech, Technology newTech)
+		{
+			this._context.Update(user);
+
+			user.Technologies.Remove(oldTech);
+			user.Technologies.Add(newTech);
+
+			return await RepositoryMethods.SaveChangesAsync(this._context);
+		}
+		#endregion
+
+		#region Delete
+
 		public async Task<bool> DeleteAsync(User entity)
 		{
-			this._context
-				.Set<User>()
+			this._context.Users
 				.Remove(entity);
 
 			return await RepositoryMethods.SaveChangesAsync(this._context);
@@ -93,37 +154,70 @@ namespace DevHive.Data.Repositories
 
 			return await RepositoryMethods.SaveChangesAsync(this._context);
 		}
-	
-		//Validations
-		public bool DoesUserExist(Guid id)
+
+		public async Task<bool> RemoveLanguageFromUserAsync(User user, Language language)
 		{
-			return this._context
-				.Set<User>()
-				.Any(x => x.Id == id);
+			this._context.Update(user);
+
+			user.Langauges.Remove(language);
+
+			return await RepositoryMethods.SaveChangesAsync(this._context);
 		}
 
-		public bool DoesUserHaveThisUsername(Guid id, string username)
+		public async Task<bool> RemoveTechnologyFromUserAsync(User user, Technology technology)
 		{
-			return this._context
-				.Set<User>()
-				.Any(x => x.Id == id &&
-					x.UserName == username);
+			this._context.Update(user);
+
+			user.Technologies.Remove(technology);
+
+			return await RepositoryMethods.SaveChangesAsync(this._context);
+		}
+		#endregion
+
+		#region Validations
+
+		public async Task<bool> DoesUserExistAsync(Guid id)
+		{
+			return await this._context.Users
+				.AnyAsync(x => x.Id == id);
 		}
 
-		public async Task<bool> DoesUsernameExist(string username)
+		public async Task<bool> DoesUsernameExistAsync(string username)
 		{
-			return await this._context
-				.Set<User>()
+			return await this._context.Users
 				.AsNoTracking()
 				.AnyAsync(u => u.UserName == username);
 		}
 
-		public async Task<bool> DoesEmailExist(string email)
+		public async Task<bool> DoesEmailExistAsync(string email)
 		{
-			return await this._context
-				.Set<User>()
+			return await this._context.Users
 				.AsNoTracking()
 				.AnyAsync(u => u.Email == email);
 		}
+
+		public async Task<bool> DoesUserHaveThisFriendAsync(Guid userId, Guid friendId)
+		{
+			User user = await this._context.Users
+				.FirstOrDefaultAsync(x => x.Id == userId);
+
+			User friend = await this._context.Users
+				.FirstOrDefaultAsync(x => x.Id == friendId);
+
+			return user.Friends.Contains(friend);
+		}
+
+		public bool DoesUserHaveThisUsername(Guid id, string username)
+		{
+			return this._context.Users
+				.Any(x => x.Id == id &&
+					x.UserName == username);
+		}
+
+		public bool DoesUserHaveFriends(User user)
+		{
+			return user.Friends.Count >= 1;
+		}
+		#endregion
 	}
 }
diff --git a/src/DevHive.Services/Configurations/Mapping/LanguageMappings.cs b/src/DevHive.Services/Configurations/Mapping/LanguageMappings.cs
index 27f392d..0be9ca2 100644
--- a/src/DevHive.Services/Configurations/Mapping/LanguageMappings.cs
+++ b/src/DevHive.Services/Configurations/Mapping/LanguageMappings.cs
@@ -10,7 +10,6 @@ namespace DevHive.Services.Configurations.Mapping
 		{
 			CreateMap<LanguageServiceModel, Language>();
 			CreateMap<Language, LanguageServiceModel>();
-			CreateMap<UpdateLanguageServiceModel, Language>();
 		}
 	}
 }
\ No newline at end of file
diff --git a/src/DevHive.Services/Models/Identity/User/RegisterServiceModel.cs b/src/DevHive.Services/Models/Identity/User/RegisterServiceModel.cs
index 77f2733..74f66b4 100644
--- a/src/DevHive.Services/Models/Identity/User/RegisterServiceModel.cs
+++ b/src/DevHive.Services/Models/Identity/User/RegisterServiceModel.cs
@@ -1,7 +1,13 @@
+using System.Collections.Generic;
+using DevHive.Services.Models.Language;
+using DevHive.Services.Models.Technology;
+
 namespace DevHive.Services.Models.Identity.User
 {
 	public class RegisterServiceModel : BaseUserServiceModel
-	{ 
+	{
+		public IList<LanguageServiceModel> Languages { get; set; }
+		public IList<TechnologyServiceModel> Technologies { get; set; }
 		public string Password { get; set; }
 	}
 }
diff --git a/src/DevHive.Services/Models/Language/CreateLanguageServiceModel.cs b/src/DevHive.Services/Models/Language/CreateLanguageServiceModel.cs
new file mode 100644
index 0000000..75e7714
--- /dev/null
+++ b/src/DevHive.Services/Models/Language/CreateLanguageServiceModel.cs
@@ -0,0 +1,9 @@
+using System;
+
+namespace DevHive.Services.Models.Language
+{
+	public class CreateLanguageServiceModel : LanguageServiceModel
+	{
+		public string Name { get; set; }
+	}
+}
diff --git a/src/DevHive.Services/Models/Language/LanguageServiceModel.cs b/src/DevHive.Services/Models/Language/LanguageServiceModel.cs
index f06ebb6..a07aa16 100644
--- a/src/DevHive.Services/Models/Language/LanguageServiceModel.cs
+++ b/src/DevHive.Services/Models/Language/LanguageServiceModel.cs
@@ -1,7 +1,9 @@
+using System;
+
 namespace DevHive.Services.Models.Language
 {
 	public class LanguageServiceModel
 	{
-		public string Name { get; set; }
+		public Guid Id { get; set; }
 	}
 }
diff --git a/src/DevHive.Services/Models/Language/UpdateLanguageServiceModel.cs b/src/DevHive.Services/Models/Language/UpdateLanguageServiceModel.cs
index 30194dd..fdc309e 100644
--- a/src/DevHive.Services/Models/Language/UpdateLanguageServiceModel.cs
+++ b/src/DevHive.Services/Models/Language/UpdateLanguageServiceModel.cs
@@ -1,9 +1,4 @@
-using System;
-
 namespace DevHive.Services.Models.Language
 {
-	public class UpdateLanguageServiceModel : LanguageServiceModel
-	{
-		public Guid Id { get; set; }
-	}
+	public class UpdateLanguageServiceModel : CreateLanguageServiceModel { }
 }
diff --git a/src/DevHive.Services/Services/LanguageService.cs b/src/DevHive.Services/Services/LanguageService.cs
index 3c011c6..127bde4 100644
--- a/src/DevHive.Services/Services/LanguageService.cs
+++ b/src/DevHive.Services/Services/LanguageService.cs
@@ -2,25 +2,25 @@ using System;
 using System.Threading.Tasks;
 using AutoMapper;
 using DevHive.Data.Models;
-using DevHive.Data.Repositories.Contracts;
+using DevHive.Data.Repositories;
 using DevHive.Services.Models.Language;
 
 namespace DevHive.Services.Services
 {
 	public class LanguageService
 	{
-		private readonly ILanguageRepository _languageRepository;
+		private readonly LanguageRepository _languageRepository;
 		private readonly IMapper _languageMapper;
 
-		public LanguageService(ILanguageRepository languageRepository, IMapper mapper)
+		public LanguageService(LanguageRepository languageRepository, IMapper mapper)
 		{
 			this._languageRepository = languageRepository;
 			this._languageMapper = mapper;
 		}
 
-		public async Task<bool> CreateLanguage(LanguageServiceModel languageServiceModel)
+		public async Task<bool> CreateLanguage(CreateLanguageServiceModel languageServiceModel)
 		{
-			if (await this._languageRepository.DoesLanguageNameExist(languageServiceModel.Name))
+			if (await this._languageRepository.DoesLanguageNameExistAsync(languageServiceModel.Name))
 				throw new ArgumentException("Language already exists!");
 
 			Language language = this._languageMapper.Map<Language>(languageServiceModel);
@@ -33,7 +33,7 @@ namespace DevHive.Services.Services
 		{
 			Language language = await this._languageRepository.GetByIdAsync(id);
 
-			if(language == null)
+			if (language == null)
 				throw new ArgumentException("The language does not exist");
 
 			return this._languageMapper.Map<LanguageServiceModel>(language);
@@ -41,28 +41,28 @@ namespace DevHive.Services.Services
 
 		public async Task<bool> UpdateLanguage(UpdateLanguageServiceModel languageServiceModel)
 		{
-			if (!await this._languageRepository.DoesLanguageExist(languageServiceModel.Id))
-				throw new ArgumentException("Language does not exist!");
+			Task<bool> langExist = this._languageRepository.DoesLanguageExistAsync(languageServiceModel.Id);
+			Task<bool> newLangNameExists = this._languageRepository.DoesLanguageNameExistAsync(languageServiceModel.Name);
 
-			if (await this._languageRepository.DoesLanguageNameExist(languageServiceModel.Name))
-				throw new ArgumentException("Language name already exists!");
+			await Task.WhenAny(langExist, newLangNameExists);
 
-			Language language = this._languageMapper.Map<Language>(languageServiceModel);
-			//language.Id = languageServiceModel.Id;
-			bool result = await this._languageRepository.EditAsync(language);
+			if (!langExist.Result)
+				throw new ArgumentException("Language already exists!");
 
-			return result;
+			if (newLangNameExists.Result)
+				throw new ArgumentException("This name is already in our datbase!");
+
+			Language lang = this._languageMapper.Map<Language>(languageServiceModel);
+			return await this._languageRepository.EditAsync(lang);
 		}
-	
+
 		public async Task<bool> DeleteLanguage(Guid id)
 		{
-			if (!await this._languageRepository.DoesLanguageExist(id))
+			if (!await this._languageRepository.DoesLanguageExistAsync(id))
 				throw new ArgumentException("Language does not exist!");
 
 			Language language = await this._languageRepository.GetByIdAsync(id);
-			bool result = await this._languageRepository.DeleteAsync(language);
-
-			return result;
+			return await this._languageRepository.DeleteAsync(language);
 		}
 	}
 }
\ No newline at end of file
diff --git a/src/DevHive.Services/Services/PostService.cs b/src/DevHive.Services/Services/PostService.cs
index e0a2be9..321c694 100644
--- a/src/DevHive.Services/Services/PostService.cs
+++ b/src/DevHive.Services/Services/PostService.cs
@@ -7,17 +7,17 @@ using DevHive.Services.Models.Post.Comment;
 using DevHive.Services.Models.Post.Post;
 using System.IdentityModel.Tokens.Jwt;
 using System.Security.Claims;
-using DevHive.Data.Repositories.Contracts;
+using DevHive.Data.Repositories;
 
 namespace DevHive.Services.Services
 {
 	public class PostService
 	{
-		private readonly IPostRepository _postRepository;
-		private readonly IUserRepository _userRepository;
+		private readonly PostRepository _postRepository;
+		private readonly UserRepository _userRepository;
 		private readonly IMapper _postMapper;
 
-		public PostService(IPostRepository postRepository, IUserRepository userRepository , IMapper postMapper)
+		public PostService(PostRepository postRepository, UserRepository userRepository , IMapper postMapper)
 		{
 			this._postRepository = postRepository;
 			this._userRepository = userRepository;
diff --git a/src/DevHive.Services/Services/RoleService.cs b/src/DevHive.Services/Services/RoleService.cs
index 372984d..7ba0a98 100644
--- a/src/DevHive.Services/Services/RoleService.cs
+++ b/src/DevHive.Services/Services/RoleService.cs
@@ -3,16 +3,16 @@ using System.Threading.Tasks;
 using AutoMapper;
 using DevHive.Common.Models.Identity;
 using DevHive.Data.Models;
-using DevHive.Data.Repositories.Contracts;
+using DevHive.Data.Repositories;
 
 namespace DevHive.Services.Services
 {
 	public class RoleService
 	{
-		private readonly IRoleRepository _roleRepository;
+		private readonly RoleRepository _roleRepository;
 		private readonly IMapper _roleMapper;
 
-		public RoleService(IRoleRepository roleRepository, IMapper mapper)
+		public RoleService(RoleRepository roleRepository, IMapper mapper)
 		{
 			this._roleRepository = roleRepository;
 			this._roleMapper = mapper;
diff --git a/src/DevHive.Services/Services/TechnologyService.cs b/src/DevHive.Services/Services/TechnologyService.cs
index e03d4d1..2913a55 100644
--- a/src/DevHive.Services/Services/TechnologyService.cs
+++ b/src/DevHive.Services/Services/TechnologyService.cs
@@ -2,17 +2,17 @@ using System;
 using System.Threading.Tasks;
 using AutoMapper;
 using DevHive.Data.Models;
-using DevHive.Data.Repositories.Contracts;
+using DevHive.Data.Repositories;
 using DevHive.Services.Models.Technology;
 
 namespace DevHive.Services.Services
 {
 	public class TechnologyService
 	{
-		private readonly ITechnologyRepository _technologyRepository;
+		private readonly TechnologyRepository _technologyRepository;
 		private readonly IMapper _technologyMapper;
 
-		public TechnologyService(ITechnologyRepository technologyRepository, IMapper technologyMapper)
+		public TechnologyService(TechnologyRepository technologyRepository, IMapper technologyMapper)
 		{
 			this._technologyRepository = technologyRepository;
 			this._technologyMapper = technologyMapper;
diff --git a/src/DevHive.Services/Services/UserService.cs b/src/DevHive.Services/Services/UserService.cs
index c8bcab9..e1f925d 100644
--- a/src/DevHive.Services/Services/UserService.cs
+++ b/src/DevHive.Services/Services/UserService.cs
@@ -11,28 +11,40 @@ using System.Security.Cryptography;
 using System.Text;
 using System.Collections.Generic;
 using DevHive.Common.Models.Identity;
-using DevHive.Data.Repositories.Contracts;
+using DevHive.Services.Models.Language;
+using DevHive.Data.Repositories;
 
 namespace DevHive.Services.Services
 {
 	public class UserService
 	{
-		private readonly IUserRepository _userRepository;
-		private readonly IRoleRepository _roleRepository;
+		private readonly UserRepository _userRepository;
+		private readonly RoleRepository _roleRepository;
+		private readonly LanguageRepository _languageRepository;
+		private readonly TechnologyRepository _technologyRepository;
 		private readonly IMapper _userMapper;
 		private readonly JWTOptions _jwtOptions;
 
-		public UserService(IUserRepository userRepository, IRoleRepository roleRepository, IMapper mapper, JWTOptions jwtOptions)
+		public UserService(UserRepository userRepository,
+			LanguageRepository languageRepository,
+			RoleRepository roleRepository,
+			TechnologyRepository technologyRepository,
+			IMapper mapper,
+			JWTOptions jwtOptions)
 		{
 			this._userRepository = userRepository;
 			this._roleRepository = roleRepository;
 			this._userMapper = mapper;
 			this._jwtOptions = jwtOptions;
+			this._languageRepository = languageRepository;
+			this._technologyRepository = technologyRepository;
 		}
 
+		#region Authentication
+
 		public async Task<TokenModel> LoginUser(LoginServiceModel loginModel)
 		{
-			if (!await this._userRepository.DoesUsernameExist(loginModel.UserName))
+			if (!await this._userRepository.DoesUsernameExistAsync(loginModel.UserName))
 				throw new ArgumentException("Invalid username!");
 
 			User user = await this._userRepository.GetByUsername(loginModel.UserName);
@@ -45,10 +57,10 @@ namespace DevHive.Services.Services
 
 		public async Task<TokenModel> RegisterUser(RegisterServiceModel registerModel)
 		{
-			if (await this._userRepository.DoesUsernameExist(registerModel.UserName))
+			if (await this._userRepository.DoesUsernameExistAsync(registerModel.UserName))
 				throw new ArgumentException("Username already exists!");
 
-			if (await this._userRepository.DoesEmailExist(registerModel.Email))
+			if (await this._userRepository.DoesEmailExistAsync(registerModel.Email))
 				throw new ArgumentException("Email already exists!");
 
 			User user = this._userMapper.Map<User>(registerModel);
@@ -66,20 +78,58 @@ namespace DevHive.Services.Services
 
 			return new TokenModel(WriteJWTSecurityToken(user.UserName, user.Roles));
 		}
+		#endregion
+
+		#region Create
 
 		public async Task<bool> AddFriend(Guid userId, Guid friendId)
 		{
-			User user = await this._userRepository.GetByIdAsync(userId);
-			User friend = await this._userRepository.GetByIdAsync(friendId);
+			Task<bool> userExists = this._userRepository.DoesUserExistAsync(userId);
+			Task<bool> friendExists = this._userRepository.DoesUserExistAsync(friendId);
+
+			await Task.WhenAll(userExists, friendExists);
+
+			if (!userExists.Result)
+				throw new ArgumentException("User doesn't exist!");
 
-			if (DoesUserHaveThisFriend(user, friend))
+			if (!friendExists.Result)
+				throw new ArgumentException("Friend doesn't exist!");
+
+			if (await this._userRepository.DoesUserHaveThisFriendAsync(userId, friendId))
 				throw new ArgumentException("Friend already exists in your friends list.");
 
-			return user != default(User) && friend != default(User) ? 
-				await this._userRepository.AddFriendAsync(user, friend) : 
+			User user = await this._userRepository.GetByIdAsync(userId);
+			User friend = await this._userRepository.GetByIdAsync(friendId);
+
+			return user != default(User) && friend != default(User) ?
+				await this._userRepository.AddFriendAsync(user, friend) :
 				throw new ArgumentException("Invalid user!");
 		}
 
+		public async Task<bool> AddLanguageToUser(Guid userId, LanguageServiceModel languageServiceModel)
+		{
+			Task<bool> userExists = this._userRepository.DoesUserExistAsync(userId);
+			Task<bool> languageExists = this._languageRepository.DoesLanguageExistAsync(languageServiceModel.Id);
+
+			await Task.WhenAll(userExists, languageExists);
+
+			if (!userExists.Result)
+				throw new ArgumentException("User does not exist!");
+
+			if (!languageExists.Result)
+				throw new ArgumentException("Language does not exist!");
+
+			Task<User> user = this._userRepository.GetByIdAsync(userId);
+			Task<Language> language = this._languageRepository.GetByIdAsync(languageServiceModel.Id);
+
+			await Task.WhenAll(user, language);
+
+			return await this._userRepository.AddLanguageToUserAsync(user.Result, language.Result);
+		}
+		#endregion
+
+		#region Read
+
 		public async Task<UserServiceModel> GetUserById(Guid id)
 		{
 			User user = await this._userRepository.GetByIdAsync(id)
@@ -90,21 +140,24 @@ namespace DevHive.Services.Services
 
 		public async Task<UserServiceModel> GetFriendById(Guid friendId)
 		{
-			if(!_userRepository.DoesUserExist(friendId))
+			if (!await _userRepository.DoesUserExistAsync(friendId))
 				throw new ArgumentException("User does not exist!");
 
 			User friend = await this._userRepository.GetByIdAsync(friendId);
 
 			return this._userMapper.Map<UserServiceModel>(friend);
 		}
+		#endregion
+
+		#region Update
 
 		public async Task<UserServiceModel> UpdateUser(UpdateUserServiceModel updateModel)
 		{
-			if (!this._userRepository.DoesUserExist(updateModel.Id))
+			if (!await this._userRepository.DoesUserExistAsync(updateModel.Id))
 				throw new ArgumentException("User does not exist!");
 
 			if (!this._userRepository.DoesUserHaveThisUsername(updateModel.Id, updateModel.UserName)
-					&& await this._userRepository.DoesUsernameExist(updateModel.UserName))
+					&& await this._userRepository.DoesUsernameExistAsync(updateModel.UserName))
 				throw new ArgumentException("Username already exists!");
 
 			User user = this._userMapper.Map<User>(updateModel);
@@ -113,12 +166,15 @@ namespace DevHive.Services.Services
 			if (!result)
 				throw new InvalidOperationException("Unable to edit user!");
 
-			return this._userMapper.Map<UserServiceModel>(user);;
+			return this._userMapper.Map<UserServiceModel>(user); ;
 		}
+		#endregion
+
+		#region Delete
 
 		public async Task DeleteUser(Guid id)
 		{
-			if (!this._userRepository.DoesUserExist(id))
+			if (!await this._userRepository.DoesUserExistAsync(id))
 				throw new ArgumentException("User does not exist!");
 
 			User user = await this._userRepository.GetByIdAsync(id);
@@ -130,21 +186,25 @@ namespace DevHive.Services.Services
 
 		public async Task<bool> RemoveFriend(Guid userId, Guid friendId)
 		{
-			if(!this._userRepository.DoesUserExist(userId) && 
-				!this._userRepository.DoesUserExist(friendId))
-					throw new ArgumentException("Invalid user!");
+			Task<bool> userExists = this._userRepository.DoesUserExistAsync(userId);
+			Task<bool> friendExists = this._userRepository.DoesUserExistAsync(friendId);
 
-			User user = await this._userRepository.GetByIdAsync(userId);
-			User friend = await this._userRepository.GetByIdAsync(friendId);
+			await Task.WhenAll(userExists, friendExists);
+
+			if (!userExists.Result)
+				throw new ArgumentException("User doesn't exist!");
 
-			if(!this.DoesUserHaveFriends(user))
-				throw new ArgumentException("User does not have any friends.");
+			if (!friendExists.Result)
+				throw new ArgumentException("Friend doesn't exist!");
 
-			if (!DoesUserHaveThisFriend(user, friend))
+			if (!await this._userRepository.DoesUserHaveThisFriendAsync(userId, friendId))
 				throw new ArgumentException("This ain't your friend, amigo.");
 
-			return await this.RemoveFriend(user.Id, friendId);
+			return await this.RemoveFriend(userId, friendId);
 		}
+		#endregion
+
+		#region Validations
 
 		public async Task<bool> ValidJWT(Guid id, string rawTokenData)
 		{
@@ -153,7 +213,7 @@ namespace DevHive.Services.Services
 
 			string jwtUserName = this.GetClaimTypeValues("unique_name", jwt.Claims)[0];
 			List<string> jwtRoleNames = this.GetClaimTypeValues("role", jwt.Claims);
-			
+
 			User user = await this._userRepository.GetByUsername(jwtUserName)
 				?? throw new ArgumentException("User does not exist!");
 
@@ -164,9 +224,9 @@ namespace DevHive.Services.Services
 					return false;
 
 			/* Check roles */
-			
+
 			// Check if jwt contains all user roles (if it doesn't, jwt is either old or tampered with)
-			foreach(var role in user.Roles)
+			foreach (var role in user.Roles)
 			{
 				if (!jwtRoleNames.Contains(role.Name))
 					return false;
@@ -179,26 +239,11 @@ namespace DevHive.Services.Services
 			return true;
 		}
 
-		private string GeneratePasswordHash(string password)
-		{
-			return string.Join(string.Empty, SHA512.HashData(Encoding.ASCII.GetBytes(password)));
-		}
-
-		private bool DoesUserHaveThisFriend(User user, User friend)
-		{
-			return user.Friends.Contains(friend);
-		}
-
-		private bool DoesUserHaveFriends(User user)
-		{
-			return user.Friends.Count >= 1;
-		}
-
 		private List<string> GetClaimTypeValues(string type, IEnumerable<Claim> claims)
 		{
 			List<string> toReturn = new();
-			
-			foreach(var claim in claims)
+
+			foreach (var claim in claims)
 				if (claim.Type == type)
 					toReturn.Add(claim.Value);
 
@@ -214,7 +259,7 @@ namespace DevHive.Services.Services
 				new Claim(ClaimTypes.Name, userName),
 			};
 
-			foreach(var role in roles)
+			foreach (var role in roles)
 			{
 				claims.Add(new Claim(ClaimTypes.Role, role.Name));
 			}
@@ -232,5 +277,12 @@ namespace DevHive.Services.Services
 			SecurityToken token = tokenHandler.CreateToken(tokenDescriptor);
 			return tokenHandler.WriteToken(token);
 		}
+
+		private string GeneratePasswordHash(string password)
+		{
+			return string.Join(string.Empty, SHA512.HashData(Encoding.ASCII.GetBytes(password)));
+		}
+
+		#endregion
 	}
 }
diff --git a/src/DevHive.Tests/DevHive.Data.Tests/TechnologyRepository.Tests.cs b/src/DevHive.Tests/DevHive.Data.Tests/TechnologyRepository.Tests.cs
index ee0ca4b..beac798 100644
--- a/src/DevHive.Tests/DevHive.Data.Tests/TechnologyRepository.Tests.cs
+++ b/src/DevHive.Tests/DevHive.Data.Tests/TechnologyRepository.Tests.cs
@@ -34,7 +34,7 @@ namespace DevHive.Data.Tests
             this.Context.Database.EnsureDeleted();
         }
 
-        #region AddAync
+        #region AddAsync
         [Test]
         public void AddAsync_AddsTheGivenTechnologyToTheDatabase()
         {
@@ -127,7 +127,7 @@ namespace DevHive.Data.Tests
             {
                 bool result = await this.TechnologyRepository.DoesTechnologyNameExist(TECHNOLOGY_NAME);
 
-                Assert.False(result, "DoesTechnologyNameExist returns true when tehcnology name does not exist");
+                Assert.False(result, "DoesTechnologyNameExist returns true when technology name does not exist");
             }).GetAwaiter().GetResult();
         }
         #endregion
diff --git a/src/DevHive.Web/Configurations/Mapping/LanguageMappings.cs b/src/DevHive.Web/Configurations/Mapping/LanguageMappings.cs
index 5715b13..bae8562 100644
--- a/src/DevHive.Web/Configurations/Mapping/LanguageMappings.cs
+++ b/src/DevHive.Web/Configurations/Mapping/LanguageMappings.cs
@@ -9,9 +9,12 @@ namespace DevHive.Web.Configurations.Mapping
 		public LanguageMappings()
 		{
 			CreateMap<LanguageWebModel, LanguageServiceModel>();
-			CreateMap<UpdateLanguageWebModel, LanguageServiceModel>();
+			CreateMap<CreateLanguageWebModel, CreateLanguageServiceModel>();
+			CreateMap<UpdateLanguageWebModel, UpdateLanguageServiceModel>();
+
 			CreateMap<LanguageServiceModel, LanguageWebModel>();
-			CreateMap<LanguageWebModel, UpdateLanguageServiceModel>();
+			CreateMap<CreateLanguageServiceModel, CreateLanguageWebModel>();
+			CreateMap<UpdateLanguageServiceModel, UpdateLanguageWebModel>();
 		}
 	} 
 }
\ No newline at end of file
diff --git a/src/DevHive.Web/Controllers/LanguageController.cs b/src/DevHive.Web/Controllers/LanguageController.cs
index d71d622..29c1e99 100644
--- a/src/DevHive.Web/Controllers/LanguageController.cs
+++ b/src/DevHive.Web/Controllers/LanguageController.cs
@@ -23,9 +23,9 @@ namespace DevHive.Web.Controllers
 		}
 
 		[HttpPost]
-		public async Task<IActionResult> Create([FromBody] LanguageWebModel languageWebModel)
+		public async Task<IActionResult> Create([FromBody] CreateLanguageWebModel createLanguageWebModel)
 		{
-			LanguageServiceModel languageServiceModel = this._languageMapper.Map<LanguageServiceModel>(languageWebModel);
+			CreateLanguageServiceModel languageServiceModel = this._languageMapper.Map<CreateLanguageServiceModel>(createLanguageWebModel);
 
 			bool result = await this._languageService.CreateLanguage(languageServiceModel);
 
diff --git a/src/DevHive.Web/Models/Language/CreateLanguageWebModel.cs b/src/DevHive.Web/Models/Language/CreateLanguageWebModel.cs
new file mode 100644
index 0000000..111beed
--- /dev/null
+++ b/src/DevHive.Web/Models/Language/CreateLanguageWebModel.cs
@@ -0,0 +1,9 @@
+using System;
+
+namespace DevHive.Web.Models.Language
+{
+	public class CreateLanguageWebModel : LanguageWebModel
+	{
+		public string Name { get; set; }
+	}
+}
\ No newline at end of file
diff --git a/src/DevHive.Web/Models/Language/LanguageWebModel.cs b/src/DevHive.Web/Models/Language/LanguageWebModel.cs
index 1ec38f3..455b559 100644
--- a/src/DevHive.Web/Models/Language/LanguageWebModel.cs
+++ b/src/DevHive.Web/Models/Language/LanguageWebModel.cs
@@ -1,7 +1,9 @@
+using System;
+
 namespace DevHive.Web.Models.Language
 {
 	public class LanguageWebModel
 	{
-		public string Name { get; set; }
+		public Guid Id { get; set; }
 	}
 }
\ No newline at end of file
diff --git a/src/DevHive.Web/Models/Language/UpdateLanguageWebModel.cs b/src/DevHive.Web/Models/Language/UpdateLanguageWebModel.cs
index 26eb6c2..2da8217 100644
--- a/src/DevHive.Web/Models/Language/UpdateLanguageWebModel.cs
+++ b/src/DevHive.Web/Models/Language/UpdateLanguageWebModel.cs
@@ -2,8 +2,5 @@ using System;
 
 namespace DevHive.Web.Models.Language
 {
-	public class UpdateLanguageWebModel : LanguageWebModel
-	{
-		public Guid Id { get; set; }
-	}
+	public class UpdateLanguageWebModel : CreateLanguageWebModel {}
 }
\ No newline at end of file