GitHub User: tbarho
The best way i've found to do this is to just add a route in your routes file like:
match '/editor(/*requested_uri)' => 'mercury_auth#edit', :as => :mercury_editor
Then create a new controller that inherits from MercuryController, like:
class MercuryAuthController < MercuryController
before_filter :authenticate_with_admin, :only => [:edit]
render :text => '', :layout => 'mercury'
Then, you can get all the functionality of Mercury, but limit access on requests like that. That might be a bit closer to what you were looking for.
Oh, and be sure to add that route before the mercury routes in your routes.rb file