Deploying your site was a recipe for pain before git. Now you just need to do a pull and you're done, right? Well, you have to run DB updates, and clear the cache and revert your features, and you forgot to .gitignore that file so your pull failed and -- ARGH! It all culminates in DEEP HURTING.
At TEN7, we built our own CI bliss by combining Ansible with Gitlab CI. Our lightweight solution is not only built on free and open source components, the CI code itself is on Github!
Take a look and find out how we built push-to-deploy in Tess Flynn's Drupalcon session!