CircuitStudio doesn't support GIT version control, so that would have to be done externally to CircuitStudio. The software won't be affected by it so there is nothing wrong with this approach, but it won't be aware of the versions etc.
CircuitStudio has inbuilt support for Subversion (SVN) out of the box so you can make a repository and connect to it and then see the status of each file within the Projects panel or the Storage Manager panel. The Storage Manager allows previous revisions to be compared visually.
