public function all($n = null, $published = true)
{
$posts = $this->model->select('id', 'title', 'summary', 'comment_count', 'view_count', 'favorite_count', 'created_at', 'slug', 'published')->orderBy('created_at', 'desc');
if ($published) {
$posts = $posts->wherePublished(true);
}
return $n ? $posts->paginate($n) : $posts->get();
}