Recurring Push Notifications

I’m really enthusiastic about the OneSignal addition to Android & iOS, but I can really only see how to make single-time push notifications through this.
Is there any method to generate routine, once a week notifications on the user’s phone? The message will never have to be customized. I can imagine one could hack this as an error-pop up while the app is in the background, or something, but I’m not sure how to implement it. Thanks!