MonkeyPatch UrlHelper for broken routing

> When there's an optional scope, `link_to resource` doesn't seem to work
> properly in rails 4

The fix was taken from https://git.io/v6otV. It looks like this is still
an issue, so we might want to extract this monkeypatch out in to its own
file if it's still broken by the time we get to Rails 4.2.

- svenfuchs/routing-filter#47
- rails/rails#12178
- rails/rails#22767

lib/routing_filters.rb

@@ -33,3 +33,9 @@ def locales=(locales)
     end
   end
 end
+
+ActionDispatch::Routing::RouteSet::NamedRouteCollection::UrlHelper.class_eval do
+  def self.optimize_helper?(route)
+    false
+  end
+end