start working on custom chat handlers

CustomChatAddOns/Options/CustomChatHandler.cs

@@ -0,0 +1,19 @@
+using Kruzya.TelegramBot.Core.Options;
+
+namespace Kruzya.TelegramBot.CustomChatAddOns.Options
+{
+    public class CustomChatHandler : AbstractOption<CustomChatHandler, string>
+    {
+        public CustomChatHandler(IOptionProvider optionProvider) : base(optionProvider)
+        {
+        }
+
+        public override string OptionId => "customChatHandlerUrl";
+
+        public override string OptionName => "Custom Chat Handler";
+
+        public override OptionType OptionType => OptionType.Hidden;
+
+        public override string DefaultValue => "";
+    }
+}