For those who don't know, github is a site where you can upload your code for your team to work on or for other people to see.
Most possibly the best place to manage and work with code in a team. Open source projects are free to host no matter the size, but if you want a private project, you are going to need to pay $7/month to maintain a private repo.
If you're a programmer and you don't know git, you need to learn it. Arguably the best version control on the planet.