public function store(Request $request)
 {
     $this->validate($request, ['title' => 'required|min:6', 'body' => 'required']);
     $data = $request->all();
     $data['alias'] = empty($data['alias']) ? str_replace(" ", "-", $data['title']) : str_replace(" ", "-", $data['alias']);
     $data['user_id'] = \Auth::id();
     $data['published'] = $request->has('published');
     $post = Post::create($data);
     $category_posts = [];
     foreach ($request->get('categories') as $category_id) {
         $category_posts[] = ['post_id' => $post->id, 'category_id' => $category_id];
     }
     CategoryPost::insert($category_posts);
     return redirect('/admin/posts');
 }