how to fill in entity field with logged in user with a certain role

->add('instructor', EntityType::class, [
                'class' => User::class,
                'choice_label' => 'name',
                'multiple' => false,
                'query_builder' => function (EntityRepository $er) {
                    return $er->createQueryBuilder('u')
                        ->where('u.roles LIKE :role')
                        ->setParameter('role', '%ROLE_INSTRUCTOR%');
                },
            ])

right now i only got a dropdown from all instructors