/**
  * Display a listing of the articles.
  *
  * @return \Illuminate\Http\Response
  */
 public function index()
 {
     /*
      * --------------------------------------------------------------------------
      * Filtering article
      * --------------------------------------------------------------------------
      * Populate optional filter on url break down in data, sorting by and sorting
      * method, retrieve the article.
      */
     $filter_data = Input::has('data') ? Input::get('data') : 'all';
     $filter_status = Input::has('status') ? Input::get('status') : 'all';
     $filter_by = Input::has('by') ? Input::get('by') : 'date';
     $filter_sort = Input::has('sort') ? Input::get('sort') : 'desc';
     $query = Input::has('query') ? Input::get('query') : null;
     $articles = $this->article->retrieveArticle($filter_data, $filter_status, $filter_by, $filter_sort, $query);
     return view('admin.article.index', compact('articles'));
 }