* Tests for migration 23
* Make the migration more robust
For duplicate foreign Ids, create dummy id so correlated subquery
doesn't fail.
If we can't parse the release from the database, put in a dummy release.
* Be more careful with metadata refreshes
Make sure we deal with items that are not linked to the correct parent
* New: Store all releases for an album and track artists
* Add Overview, links and release date by release
* Tidy up
* Fix metadata refresh errors following musicbrainz edits