- Reorder the code inside the methods to fail fast on autorization,
- Replace `int_or_none` with a more generic solution, and move to utils,
- Add `get_values` and move `pk_and_slug` as `get_pk_and_slug` into utils,
- Replace calls to static methos in models local queries,
- Return meaningful status code while creating and updating resources,
- Return `409` when creating or updating a schedule produces a conflict.

- update the model
- migrate the model
- update the serializer
- update the views

Add pipeline to build and push to docker hub
    when there is a new commit to main: tagged as unstable
    when a tag is pushed: tagged as latest and with the tag
        afterwards create a release in gitlab when pushing was successful

- updated the fixture
- updated the serializer
- updated some views