public function findAllCategoriesBySupermarket($supermarket)
        {
            return $this->getEntityManager()
                ->createQuery(
                    "SELECT p.supermarketId, c.categoryName, c.categorySlug
                    FROM AppBundle:Product p
                    JOIN AppBundle:Category c
                    WHERE p.supermarketId = $supermarket"
                )
                ->getResult();
        }