Because of the shared nature of hosting here at Dreamhost, you can’t run the standalone server without violating the terms of service. You MUST use apache to route requests to your ruby app to “Play Nice” on DH.
The wiki has lots of info on lots of topics - one is Ruby on Rails
See if that helps you.
Wholly - Use promo code WhollyMindless for full 97$ credit. Let me know if you want something else!