func RandomStringFrom(n int, base []rune) string {
	runes := make([]rune, n)
	for id := range runes {
		runes[id] = base[rand.Intn(len(base))]
	}
	return string(runes)
}
RandomStringFrom generates random string from base runes
package utils
import "math/rand"
var (
	randomBase = []rune("abcdefghijklmnopqrstuvwxyz0123456789")
)
type StringList []string
func (s StringList) Has(i string) bool {
	for _, obj := range s {
		if obj == i {
			return true
		}
	}
	return false
}
func (s StringList) Append(i ...string) StringList {
	return append(s, i...)
}
func (s StringList) Remove(i ...string) StringList {
	r := make(StringList, 0, len(s))
	strings := StringList(i)
	for _, obj := range s {
		if strings.Has(obj) {
			continue
		}
		r = r.Append(obj)
	}
	return r
}
func RandomString(n int) string {
	return RandomStringFrom(n, randomBase)
}