public function addFavorite()
 {
     $this->authUserOr403();
     $idea = $this->findIdeaOr404($this->request->get('id'));
     $favorite = new FavoriteIdea();
     $favorite->user_id = $this->user->id;
     $favorite->idea_id = $idea->id;
     $favorite->save();
     return redirect()->action('IdeaController@view', ['id' => $idea->id]);
 }