discovery: Add hierarchical model for chatroom invitation

Change-Id: I19e74745a5998fe075a373357df542fef317ae5f
diff --git a/src/chatroom-discovery-backend.hpp b/src/chatroom-discovery-backend.hpp
index fe5e211..986c3a1 100644
--- a/src/chatroom-discovery-backend.hpp
+++ b/src/chatroom-discovery-backend.hpp
@@ -119,9 +119,10 @@
    * @brief send chatroom info to front end
    *
    * @param info the chatroom info request by front end
+   * @param isParticipant if the user is a participant of the chatroom
    */
   void
-  chatroomInfoReady(const ChatroomInfo& info);
+  chatroomInfoReady(const ChatroomInfo& info, bool isParticipant);
 
 public slots: