That's a simple way of putting what GitHub is - a version control system. I think this helps a lot of people who use GitHub for the first time.
Keep working on your article series. I'll keep reading them! If you want to add an article about pull requests and commit reviews let me know. That's what we do at Codacy. We make sure you automatically check for issues on every commit and pull requests on your repositories so you keep your code clean. Feel free to take a look at my blog page.