rails/rails — pull request #11096 by akalyaev (2013-06-25 18:33:37+00:00)
Title: removed unnecessary mapping for on options

Right before that in `assert_valid_transaction_action` method we make
sure that `options[:on]` contains values from `ACTIONS` array
(`[:create, :destroy, :update]`) and nothing more (i.e. it could not
contain strings or something else, otherwise the error is raised).

Also I've polished some docs.