user/id.go
func NextGID() (int, error) {
	db, gid, err := nextGUID(false)
	db.close()
	return gid, err
}
func NextGID() (int, error) {
	db, gid, err := nextGUID(false)
	db.close()
	return gid, err
}
// NextGID returns the next free group id to use.