class ActionDispatch::Routing::RouteSet

need devise_for mappings already declared to create filters and helpers.
Ensure Devise modules are included only after loading routes, because we
:nodoc:

def finalize_with_devise!
  finalize_without_devise!
  @devise_finalized ||= begin
    Devise.configure_warden!
    Devise.regenerate_helpers!
    true
  end
end