Comments

Card: https://trello.com/c/DOb3MOBk/10-comments-on-a-card-last-comment-at-the-top-initially-just-record-who-commented-and-what-did-they-say-that-s-all

Realtime and e-mail were too large for a single iteration, thus let’s keep them separate (as they are in cards, after all).

Please, @exalted give this a look :smile: 
Well, basically that I created a `resources :cards` with `only: []`, which is kinda weird. Deep nesting is not really recommended, so I couldn’t put this route right under the first `resources :cards` declaration.

I think we have no other choice, though :smile: