Pick something hosted that you don't have to manage. There are only a couple well supported systems.
I'm going to lose credibility with my peeps but....
VisualStudio.com is probably the easiest to spin up. We use it when we have to do a multi-company PoC or joint project. It comes with task management, scrum boards and other bits. You can set up your repositories as either TFS or as Git. They treat GIT as a first class citizen.
GIT is an expert's tool. There are several hosted repositories, GITHub , AWS Code Commit, BitBucket, the previously mentioned VisualStudio.com, etc..