public function products_related($slug)
 {
     $product = Product::findBySlug($slug);
     if (!empty($product->tags)) {
         $products = Product::findRelated($product->tags, $slug);
         if ($products) {
             return $this->_product_grid($products);
         } else {
             return null;
         }
     } else {
         return null;
     }
 }