== Initial approach ==
* [ ] New command to add/remove flag groups to/from users globally (2)
* [ ] New command to create and delete flag groups, and change flag to flag group assignments (3)
* [x] Database storage for flaggroups - `flaggroup` (db table: 1, model, mapping: 1 = 2)
* [x] Database storage for flaggroup to global user assignments - `flaggroup_user` (db table: 1, model, mapping: 1 = 2)
* [x] Existing class tidy-up (1)
* [ ] New `IFlagService` implementation (3)
* [ ] Bin old `LegacyFlagService`, `Access` command (1)
* [ ] Rip out any unused code (likely the entire legacy command system (0-5)
== Considerations ==
* Interoperability with legacy system short-term
* Migration to new data format?
* Middle-layer service to handle rights changes?