[wadehas]

Jenkins is a "Continuous Integration/Continuous Deployment" environment/tool. It is usually set up such that it will monitor your source control system of choice (Git, Subversion, etc.) and when it sees changes it will sync those changes and build the source code, and if you have them it can run tests against what it builds, and if all of that succeeds, then Jenkins can be configured to deploy the resultant build. Even if you only configure Jenkins to build changes as they come in, that alone is useful in making sure check-ins to your source control system of choice are actually buildable and not breaking.

I have experimented with Jenkins in the last couple years with FRC C++ code, and have found that the way things build (at least for C++) is a bit cumbersome and awkward in Jenkins. I did have this set up before FRC moved to the RoboRio, and it was much easier.

Git is a source control system, that should allow multiple people to work on the same code base at the same time. Other source control systems are Subversioin, CVS, Perforce. They each have their advantages and disadvantages and won't go into them here. The obvious benefit to a source control system is that it tracks change history so that if you change something, and things break, and you can't remember what you change, you can look back to see what changed and who made the change. I am not sure why you couldn't have multiple people work on the code base at the same time.