public function subcategory($category_id)
 {
     $view = $this->__common(new View(SubCategoryView));
     $view->title = 'Craiglist | ' . 'SubCategories';
     $view->isLoggedIn = Authentification::isLoggedIn();
     $model = new CategoryModel();
     $view->category = $category_id;
     $view->subcategories = $model->getSubCategories($category_id);
     $view->subcat_number = count($view->subcategories);
     print $view->display();
 }