I’ve really loving running apps on Heroku, but unfortunately their routing mesh means that they only support custom domains on a subdomain (http://www.mydomain.com), not on the raw domain (http://mydomain.com). Luckily today I discovered an option buried in the Google Apps settings to do this:

Just specify the subdomain for which you have a CNAME pointing to your Heroku app.

Then it’s just a matter of setting your DNS A records to Google’s servers. Here’s it in TransIP (the IPv6 addresses haven’t be updated):