Votes

Voting works for both articles and comments. Resolves #23. 

Rational for not-restful routes: no messy link / route changes asynchronously. Wanted to have a toggle so that clicking the vote again will destroy it (ala Reddit).
I like the way you think. Probably replace `shows` with `sees` in my previous example to make it read a bit better, now that I'm re-reading it.