login_required NoMethodError due to not including AuthenticatedSystem module
Yet another frustrating issue solved. In trying to get authentication working, I was getting this when I tried to do a prohibited action:
NoMethodError in AppsController#edit
undefined method `login_required' for #
The answer is here. I needed to include the AuthenticatedSystem module in my application controller (not the controller for the relevant object). None of these seem to be included on the install page on the Resful Authentication wiki