[FA-55] User Service backend initial setup

FictionArchive.Service.UserService/Models/Database/User.cs

@@ -6,15 +6,13 @@ namespace FictionArchive.Service.UserService.Models.Database;
 [Index(nameof(OAuthProviderId), IsUnique = true)]
 public class User : BaseEntity<Guid>
 {
-    public string Username { get; set; }
-    public string Email { get; set; }
-    public string OAuthProviderId { get; set; }
-    
-    
+    public required string Username { get; set; }
+    public required string Email { get; set; }
+    public required string OAuthProviderId { get; set; }
     public bool Disabled { get; set; }
-    
-    /// <summary>
-    /// The user that generated an invite used by this user.
-    /// </summary>
+    public int AvailableInvites { get; set; } = 0;
+
+    // Navigation properties
+    public Guid? InviterId { get; set; }
     public User? Inviter { get; set; }
 }