public function findActiveBySlug($slug)
    {
        $query = $this->createValuedQueryBuilder('c')
            ->where('c.slug = :slug')
            ->andWhere('c.active = :active')
            ->setParameters(['slug' => $slug, 'active' => true])
            ->getQuery();

        return $query->useResultCache(true, self::CACHE_TTL)->getSingleResult();
    }