public function findByUsernameContains($searched_term)
    {
        $qb = $this->createQueryBuilder('u');
        $qb instanceof QueryBuilder;

        $qb->add('where', $qb->expr()->like('u.username', $qb->expr()->lower(':searched_term')))
            ->setParameter('searched_term', $searched_term . '%');

        return $qb->getQuery()->getResult();
    }