For the schedule versioning in the admin interface (having multiple possible shcedules) we need to change some models and associations. It has also been create a rake:move_events_attributes task to migrate the data.
User Interface addapted to make use of the introduced associations and models
The controllers are not using the serializers, because of a bug in active_model_serializer.
Hence the update.API tests are fixed to work with the new API response structure.
Fixes bugs in conference serializer.