entity.admin.user.entity.class: My\WebBundle\Entity\User
admin_user.user_manager:
class: FOS\UserBundle\Doctrine\UserManager
arguments: [@security.encoder_factory, @fos_user.util.username_canonicalizer, @fos_user.util.email_canonicalizer, @fos_user.entity_manager,%entity.admin.user.entity.class% ]