Add data structures with getters/setters, etc. so the person working on
ECA-7382 can implement editing in the GUI
It should extend BasePublisher, and contain a List<Set<Integer>>, representing groups with one or more publisher Ids in them.
Note: The objects will be stored in the database with data protection, so each time it is serialized, it must generate exactly the same result. So for sets and maps (if any), it has to use LinkedHashSet and LinkedHashMap