public function create(Request $request)
 {
     $article = Article::create(['title' => $request->get('title'), 'short_description' => $request->get('short_description'), 'description' => $request->get('description')]);
     foreach ($request->get('tags') as $tagName) {
         $tag = Tag::findByName($tagName)->first();
         if (!$tag) {
             $tag = Tag::create(['title' => $tagName]);
         }
         $article->tags()->attach($tag);
     }
     return response()->json($article, 201);
 }