Split from MBS-2810

A decision was made in IRC ( http://chatlogs.musicbrainz.org/musicbrainz-devel/2011/2011-08/2011-08-03.html#T17-18-44-13103 ) to not address this that I'm not sure was based on the right understanding

The assertion was

17:20:09ocharles
it's a question of whether we should aggregate them for /ws/1 or not
17:20:21ruaok
if we didn't before, lets not do that now.

We didn't aggregate them before because there was only one level of tags; i.e. nothing to aggregate. We need to aggregate them now so the web service behaves sensibly now that we have two levels of tagging.

Facts

• there were no RG tags in classic
• so in classic, you tagged a Classic-release and you received those tags back
• release-level tags were migrated to RG tags in NGS
• NGS /ws/1 returns NGS-release group tags
• however, you tag an NGS-release and /ws/1 does not return you those tags

That seems confusing and wrong to me. You should get back both the RG tags and the release tags with merged counts, I believe; since /ws/1 only supported 1 level of tags; and to replicate the same behaviour as before, you'd need to return both. I guess I argue that this is a backwards compatibility issue- in Classic /ws/1 it was possible to retrieve all tags related to a release; whereas in NGS /ws/1 it is not.