The tutorial explains how to set up and deploy an application with a database (Heroku Postgres or MySQL ClearDB), using the log managing system provided by Heroku (Logplex) and using environment variables to define Symfony parameters thanks to the DIC.
The library automatically setups Heroku Postgres or MySQL ClearDB thanks to a Composer script.
As usual, the code and the doc are free and available on GitHub. I hope it will help people using that kind of services.
If you want to learn more about using Symfony on Heroku, Tristan Maindron talk about that topic in the Symfony conference of this week in Lille, France.