repeating expenses about abrechnung

[OlfillasOdikno]

This is probably the one most important feature I am missing in other solutions, I have implemented this feature here, works for my purposes (tracking rent, electricity bills, ...) but it's missing the UI for the mobile app and proper test cases so I don't feel that confident in up streaming it. Might still be useful for others.

[mikonse]

Awesome, from glancing over your changes I really like the idea of using recurring rules from the iCalender RFC.
The way of specifying the repeat options themselves was one of the main questions I had about this feature.

After checking out your branch and having a look I really have to say I like this way of doing it.
There are some improvements to be made in the recurring option input UI but otherwise really nice work!
If you wanna develop this further feel free, otherwise I'm probably gonna build on top of your changes once I have the time.

In case you'd like to work on your changes one main improvement would be to create a new database migration which adds the repeating field instead of adapting the existing migrations.