Symfony custom error page

Thanks,

Reading these docs:
http://brentertainment.com/other/docs/book/doctrine/dbal.html
http://brentertainment.com/other/docs/book/doctrine/orm.html
http://brentertainment.com/other/docs/reference/configuration/doctrine.html

I created this and added to my bundle services.php
http://pastebin.com/kzbPdpyg

But I get the error:

[Symfony\Component\DependencyInjection\Exception\LogicException]
Container extension “doctrine” is not registered

What more I missed to do?
Also I have no idea what ‘read’ and what ‘host’=>‘from_user_config.db’ is, I copied/pasted from a third-party application and how to inject db credentials from a separate file into this services.php?