Sometimes companies are a bit wary of using an external service such as Github for their revision control. Especially with recent outages on their service. It also costs money if you want your repository to be entirely private. You can set up your own repositories pretty easily, and even do collaboration between multiple users without much issue.
Using nothing but open source software, I've come up with a pretty cool solution that will perform builds, tests, and deployment. All of this is done once a commit to your git repository is made.