func String(n int) string {
	s := make([]rune, n)
	for i := range s {
		s[i] = alphabet[rand.Intn(len(alphabet))]
	}
	return string(s)
}
String returns a random string of length n, using the alphnum character set (a-z, A-Z, 0-9)
package randutil
import "math/rand"
var alphabet = []rune("abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789")