Merge pull request #72 from ahmdrz/master

URL in CallbackResponse Type added

types.go

@@ -190,6 +190,13 @@ type CallbackResponse struct {
 	// (Optional) If true, an alert will be shown by the client instead
 	// of a notification at the top of the chat screen. Defaults to false.
 	ShowAlert bool `json:"show_alert,omitempty"`
+	
+	// (Optional) URL that will be opened by the user's client.
+	// If you have created a Game and accepted the conditions via @Botfather
+	// specify the URL that opens your game
+	// note that this will only work if the query comes from a callback_game button.
+	// Otherwise, you may use links like telegram.me/your_bot?start=XXXX that open your bot with a parameter.
+	URL string `json:"url,omitempty"`
 }
 
 // Venue object represents a venue location with name, address and optional foursquare id.