Somewhat off-topic, but if you're looking for a good OSS CI solution, you may want to check out Strider[1]. It has far fewer features then Jenkins, but it looks nice and is incredibly easy to deploy. If you want, you can just push straight to Heroku. Of course this leaves you somewhat restricted in what tools are available, but has worked well for me for simple Python and Node.js projects.

[1] https://github.com/Strider-CD/strider/