public function getLastSubscription()
{
return InvoiceItem::join('invoices', 'invoice_id', '=', 'invoices.id')->where('subscription_from', '<>', '0000-00-00 00:00:00')->where('invoices.user_id', $this->id)->orderBy('subscription_to', 'DESC')->select('subscription_from', 'subscription_to', 'subscription_hours_quota', 'invoice_id')->first();
}
