My initial Rackup file

config.ru

use Rack::Session::Cookie, :secret => 'whatever'
use Rack::Flash
use Rack::MethodOverride

use Warden::Manager do |manager|
  manager.default_scope = :user
  manager.scope_defaults :user,         :strategies => [:password]
  manager.scope_defaults :admin,        :store => true,  :strategies => [:admin]
  manager.failure_app = Main::App
end

# handle Vendors (aka the Public)
map "/" do 
  run Main::App
end 

# handle Admins
map "/admin" do
  run Admin::App
end