4 files changed, 14 insertions, 5 deletions
diff --git a/src/DevHive.Data/Interfaces/Models/ILanguage.cs b/src/DevHive.Data/Interfaces/Models/ILanguage.cs
index f757a3f..b77d5ae 100644
--- a/src/DevHive.Data/Interfaces/Models/ILanguage.cs
+++ b/src/DevHive.Data/Interfaces/Models/ILanguage.cs
@@ -1,7 +1,12 @@
+using System.Collections.Generic;
+using DevHive.Data.Models;
+
 namespace DevHive.Data.Interfaces.Models
 {
 	public interface ILanguage : IModel
 	{
 		string Name { get; set; }
+		HashSet<User> Users { get; set; }
+
 	}
 }
diff --git a/src/DevHive.Data/Interfaces/Models/IRole.cs b/src/DevHive.Data/Interfaces/Models/IRole.cs
index 0623f07..c8b7068 100644
--- a/src/DevHive.Data/Interfaces/Models/IRole.cs
+++ b/src/DevHive.Data/Interfaces/Models/IRole.cs
@@ -5,6 +5,6 @@ namespace DevHive.Data.Interfaces.Models
 {
 	public interface IRole
 	{
-		List<User> Users { get; set; }
+		HashSet<User> Users { get; set; }
 	}
 }
diff --git a/src/DevHive.Data/Interfaces/Models/ITechnology.cs b/src/DevHive.Data/Interfaces/Models/ITechnology.cs
index 9bd97f9..153f75f 100644
--- a/src/DevHive.Data/Interfaces/Models/ITechnology.cs
+++ b/src/DevHive.Data/Interfaces/Models/ITechnology.cs
@@ -1,7 +1,11 @@
+using System.Collections.Generic;
+using DevHive.Data.Models;
+
 namespace DevHive.Data.Interfaces.Models
 {
 	public interface ITechnology : IModel
 	{
 		string Name { get; set; }
+		HashSet<User> Users { get; set; }
 	}
 }
diff --git a/src/DevHive.Data/Interfaces/Models/IUser.cs b/src/DevHive.Data/Interfaces/Models/IUser.cs
index ef8c927..08ce385 100644
--- a/src/DevHive.Data/Interfaces/Models/IUser.cs
+++ b/src/DevHive.Data/Interfaces/Models/IUser.cs
@@ -8,9 +8,9 @@ namespace DevHive.Data.Interfaces.Models
 		string FirstName { get; set; }
 		string LastName { get; set; }
 		string ProfilePictureUrl { get; set; }
-		IList<Language> Languages { get; set; }
-		IList<Technology> Technologies { get; set; }
-		IList<Role> Roles { get; set; }
-		IList<User> Friends { get; set; }
+		HashSet<Language> Languages { get; set; }
+		HashSet<Technology> Technologies { get; set; }
+		HashSet<Role> Roles { get; set; }
+		HashSet<User> Friends { get; set; }
 	}
 }