Added reference project

ref/Entities/Invite.cs

@@ -0,0 +1,48 @@
+using System;
+using System.Threading.Tasks;
+
+namespace Discord
+{
+	public class Invite : IModel<string>
+    {
+        public class ServerInfo
+		{
+			public ulong Id { get; }
+			public string Name { get; }
+		}
+		public class ChannelInfo
+		{
+			public ulong Id { get; }
+			public string Name { get; }
+		}
+		public class InviterInfo
+		{
+			public ulong Id { get; }
+			public string Name { get; }
+			public ushort Discriminator { get; }
+			public string AvatarId { get; }            
+			public string AvatarUrl { get; }
+        }
+        
+        public DiscordClient Client { get; }
+
+        string IModel<string>.Id => Code;
+        public string Code { get; }
+        public string XkcdCode { get; }
+        
+        public ServerInfo Server { get; }
+        public ChannelInfo Channel { get; }
+        public int? MaxAge { get; }
+        public int Uses { get; }
+        public int? MaxUses { get; }
+        public bool IsRevoked { get; }
+        public bool IsTemporary { get; }
+        public DateTime CreatedAt { get; }        
+        public string Url { get; }
+
+        public Task Delete() => null;
+        public Task Accept() => null;
+
+        public Task Save() => null;
+	}
+}