user Meta Fields

I would like to get your user registration code to run when Gravity form does a user registration

function user_register( $user_id ) {
		if ( isset( $_POST['expire_users'] ) && 'auto' == $_POST['expire_users'] ) {

			$expire_settings = $this->admin->settings->get_default_expire_settings();

			$expire_data = array(
				'expire_user_date_type'         => $expire_settings['expire_user_date_type'],
				'expire_user_date_in_num'       => $expire_settings['expire_user_date_in_num'],
				'expire_user_date_in_block'     => $expire_settings['expire_user_date_in_block'],
				'expire_user_date_on_timestamp' => $expire_settings['expire_timestamp'],
				'expire_user_role'              => $expire_settings['expire_user_role'],
				'expire_user_reset_password'    => $expire_settings['expire_user_reset_password'],
				'expire_user_email'             => $expire_settings['expire_user_email'],
				'expire_user_email_admin'       => $expire_settings['expire_user_email_admin']
			);

			$user = new Expire_User( $user_id );
			$user->set_expire_data( $expire_data );
			$user->save_user();
		}
	}

This is the hook for gravity forms

add_action("gform_user_registered", "add_custom_user_meta", 10, 4);
function add_custom_user_meta($user_id, $config, $entry, $user_pass) {

   update_user_meta($user_id, '_expire_user_date', $entry[1]);

}

Thanks