public function update(ArticleRequest $request, Article $article)
 {
     $article->update($request->all());
     $article->tags()->sync($request->input('tag_list'));
     return redirect('articles');
 }
 /**
  * Bootstrap the application services.
  *
  * @return void
  */
 public function boot()
 {
     view()->composer('articles.partials.nav', function ($view) {
         $view->with('latest', Article::latest()->first());
     });
 }