Contributing is always welcome!

I am no professional flask developer, if you know a better way that something can be done, please let me know!

Otherwise, it's always best to PR into the `master` branch.

Install the development and test dependencies with `pip install -r requirements-dev.txt`.

Please be sure that all new functionality has a matching test!

Use `pytest` to validate/test, you can run the existing tests as `pytest tests/test_notification.py` for example

### New dependencies

Please check the licence before adding anything to `requirements.txt`. MIT, BSD,
Apache-2.0, LGPL and MPL are fine; GPL and AGPL are not, since they would
relicense the whole project. CI enforces this. There is usually a permissive
equivalent - ask in the PR if you're not sure.