const pool = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ1234567890"

func generateId(n int) string {
	b := make([]byte, n)
	for i := range b {
		b[i] = pool[rand.Intn(len(pool))]
	}
	return string(b)
}