public function getIndex()
 {
     $conversations = Conversation::with('lastMessage', 'lastMessage.user')->withUser(Auth::id())->get()->sortBy(function ($conversation) {
         return $conversation->lastMessage->created_at;
     })->reverse();
     return $conversations;
 }
 private function getConversations()
 {
     return Conversation::with('lastMessage')->withUser(Auth::id())->get()->sortBy(function ($conversation) {
         return $conversation->lastMessage->created_at;
     })->reverse();
 }