helpers for managing counter

I'd like to create an abstraction, so that I don't need to know where
counter is stored. In this case it's stored in the session, but at
some point, this may change, and it'll be nice if this logic isn't
directly in the controller.
use helpers for counter manipulation
updated to use helpers do end
Merge pull request #2 from mikelikesbikes/counter_helpers

Counter helpers