Adding a new role with administrator’s capabilities

I found the solution to my problem. It had to do with my function that removes the manager role. I commented it out, and it works. My bad. Here’s the working code:

if ( ! ( role_exists( 'manager' ) ) ) {
    function new_role_manager() {
        global $wp_roles;

        if ( ! isset( $wp_roles ) ) {
            $wp_roles = new WP_Roles();
        }

        $adm = $wp_roles->get_role( 'administrator' );

        $wp_roles->add_role( 'manager', 'Gestionnaire', $adm->capabilities );
    }

    add_action( 'init', 'new_role_manager' );
}

Thanks