Hi chrapchp,
From our perspective, we're usually dealing with backups rather than revision control. With a backup, you should be able to restore to that point in your development. These backups can be created by Mango for you, and the JSON backup could be checked into Github and probably meaningfully diff'ed against subsequent changes (if you wanted, you could have a cron push the current JSON backup to github) but as Fox suggested that's probably not ideal for database files.
What I wanted to contribute here, though, was a suggestion that you see what's stored in the Audit database table in terms of dashboard designer pages, json store items and pages created through the "Edit pages" page. Every time you save, your previous code should be recorded into the audit table. In the future, we intend to supply a way to revert to a previous revision of a dashboard directly within Mango, without having to set up the revision control.