Add entity configuration.

darvin_menu:
    entities:

        # Prototype
        entity:

            # Whether to allow to add entities to menu in admin panel
            admin:                true

            # Whether to show entities in slug map children
            slug_children:        true

Example:

darvin_menu:
    entities:
        AppBundle\Entity\Post:
            slug_children: false
        AppBundle\Entity\PostCategory:
            admin: false