show signed in user.
signout, signin works.
play with the idea of rating: {} hash for Operation, that would allow injecting other parameters like id:. we could also use a second hash, but i find that a bit clumsy. why not leave it up to the user?
Merge branch 'master' of github.com:apotonick/gemgem

Conflicts:
	Gemfile.lock
	app/concepts/rating.rb
	test/rating/operation_test.rb