public function index($id_or_alias)
 {
     parent::load('model', 'system/contrib/auth');
     parent::load('model', 'articles');
     $articles = Article::get_by_category($id_or_alias);
     import('system/share/web/paginator');
     $paginator = new Paginator($articles, $_GET['page'], 10);
     $category = CategoryTable::getInstance()->findByAlias($id_or_alias);
     $smarty = parent::load('smarty');
     $smarty->assign('category', $category[0]);
     $smarty->assign('paginator', $paginator->output());
     $smarty->assign('page_title', $category[0]->name);
     $smarty->display('article/list');
 }