NoMethodError: Using already-defined named route in map.root call

# (part of the) content of my config/routes.rb
ActionController::Routing::Routes.draw do |map|
  map.company 'company', :controller => 'companies', :action => 'index'
  map.root :company_url
end

# In routes.rb
map.new_session :controller => 'sessions', :action => 'new'
map.root :new_session