I noticed that both the soviet-union and soviet tags exist. I propose we synonymize them, keeping the soviet-union tag, in line with the result of http://meta.history.stackexchange.com/questions/362/why-do-we-have-both-ussr-and-soviet-union-as-tags-can-we-merge-them

I noticed that both the soviet-union and soviet tags exist. I propose we synonymize them, keeping the soviet-union tag, in line with the result of Why do we have both "ussr" and "soviet union" as tags? Can we merge them?