Demonstrating the workaround per issue 917.

Change the failing code in 6f11d83 to make it pass using the workaround:

  - Explicitly include the route helpers
  - Switch to using the `_path` helper; use of the `_url` helper fails
    but with a different error:

      > Missing host to link to! Please provide the `:host` parameter, set
      > `default_url_options[:host]`, or set `:only_path` to `true`