frequency

type Frequencier interface {
	GetFrequency() *Frequency
}

type Frequency struct {
	ScheduledStartAt *time.Time
	ScheduledEndAt   *time.Time
	IntervalUnit     string // once, daily, weekly, monthly
	Interval         *int

	ActiveMonths string
	MonthDay     int
	WeekDay      int
	StartAt      string
}