pkg/flags/flag.go
func FlagToEnv(prefix, name string) string {
	return prefix + "_" + strings.ToUpper(strings.Replace(name, "-", "_", -1))
}
func FlagToEnv(prefix, name string) string {
	return prefix + "_" + strings.ToUpper(strings.Replace(name, "-", "_", -1))
}
// FlagToEnv converts flag string to upper-case environment variable key string.