public function addToCategory($categoryId)
{
if (!ProductToCategory::model()->countByAttributes(array('product_id' => $this->product_id, 'category_id' => $categoryId))) {
$productToCategory = new ProductToCategory();
$productToCategory->product_id = $this->product_id;
$productToCategory->category_id = $categoryId;
return $productToCategory->save();
}
return false;
}
