GitLab is a web-based Git repository manager with wiki and issue tracking features. GitLab is written in ruby on rails.

Installing gitlab omnibus package won't be that difficult following the guide given here. But when it comes to installing gitlab on centos 5.5, it isn't that easy as there are no omnibus packages available for centos systems with version less than 6.5. So let's look at the steps that need to be followed to make gitlab installation successful on centos 5.5:

1. Install the development tools necessary to compile applications from source