Update documentation and gate tag creation behind admin role, create default admin on database seeding

T120B165-ImgBoard/Models/User.cs

@@ -17,7 +17,4 @@ public class RefreshToken
     public DateTime Expires { get; set; }
 }
 
-public class User : IdentityUser
-{
-    //public List<Post> Posts { get; set; }
-};
+public class User : IdentityUser;