Redirect Rack app

config.ru

def redirect(arg)
  new_host = 'new.example.com'
  uri = arg["REQUEST_URI"]
  [
    302,
    {'content-type' => 'text/plain', 'location' => "http://#{new_host}#{uri}"},
    "http://#{new_host}#{uri}".chars
  ]
end
run method(:redirect)

# rackup -p 3000 -D