Get 4x the performance out of Heroku with Unicorn

Heroku provides plenty of resources, but as it only allows to listen on one port you can run only one thin instance (as recommended by their documentation).

What we need here is a webserver that listens on one port, but can work through several concurrent requests. Sounds like a job for Unicorn.

http://blog.codeship.io/2012/05/06/unicorn-on-heroku.html