public function listProductsAction($collectionId)
    {
        $pager = $this->get('sonata.product.set.manager')
            ->getProductsByCollectionIdPager($collectionId, $this->getCurrentRequest()->get('page'));

        return $this->render('SonataProductBundle:Collection:list_products.html.twig', [
            'pager' => $pager,
        ]);
    }