[FA-10] Adds user service and authentication service

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

@@ -0,0 +1,20 @@
+using FictionArchive.Service.Shared.Models;
+using Microsoft.EntityFrameworkCore;
+
+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 bool Disabled { get; set; }
+    
+    /// <summary>
+    /// The user that generated an invite used by this user.
+    /// </summary>
+    public User? Inviter { get; set; }
+}

FictionArchive.Service.UserService/Models/IntegrationEvents/AuthUserAddedEvent.cs

@@ -0,0 +1,16 @@
+using FictionArchive.Service.Shared.Services.EventBus;
+
+namespace FictionArchive.Service.UserService.Models.IntegrationEvents;
+
+public class AuthUserAddedEvent : IIntegrationEvent
+{
+    public string OAuthProviderId { get; set; }
+    
+    public string InviterOAuthProviderId { get; set; }
+
+    // The email of the user that created the event
+    public string EventUserEmail { get; set; }
+
+    // The username of the user that created the event
+    public string EventUserUsername { get; set; }
+}