developed side by side, eg development, production and feature. • Tagging speciﬁc points in the history, eg previous versions. • Merging different revisions (eg on branches) is possible. • Computers don’t (generally) muck up revisions.
powerful collaboration tools (issue trackers, wikis). • GitHub has free public repositories for Open Source, so we can involve the community in our work. • Bitbucket has a free academic tier (use lincoln.ac.uk email) which gives us private repositories.