Multiple tags/settings/warnings can exist with the same name

[Marri Nikari]

Specifically, cape setting: http://vast-journey-9935.herokuapp.com/tags/82 http://vast-journey-9935.herokuapp.com/tags/83

This was a race condition with multiple editors, because both saves would think 'cape' was a new setting, and the backend doesn't dedup. The backend should dedup.