class ActionDispatch::Routing::Mapper

def raise_no_devise_method_error!(klass) #:nodoc:
  raise "#{klass} does not respond to 'devise' method. This usually means you haven't " \
    "loaded your ORM file or it's being loaded too late. To fix it, be sure to require 'devise/orm/YOUR_ORM' " \
    "inside 'config/initializers/devise.rb' or before your application definition in 'config/application.rb'"
end