public function postIndex()
 {
     $user = Auth::getUser();
     $friendUser = null;
     if (Input::has('id')) {
         $friendUser = $this->meService->getUser(Input::get('id'));
         if ($friendUser === null) {
             return Reponse::error('User id not found');
         }
     } else {
         if (Input::has('facebook_uid')) {
             $facebook_uid = Input::get('facebook_uid');
             $friendUser = $this->registerService->preRegisterFacebookId($facebook_uid);
         } else {
             if (Input::has('email')) {
                 $email = Input::get('email');
                 $friendUser = $this->registerService->inviteByEmail($email, $user);
             } else {
                 return Response::error('Missing parameters');
             }
         }
     }
     if ($user->id === $friendUser->id) {
         return Response::error('Invited same user');
     }
     $friend = $this->meService->addFriend($user, $friendUser);
     if ($friend === null) {
         return Response::error('Failed to add friend');
     } else {
         return Response::json(['message' => 'Added new friend']);
     }
 }