The 'Transporter' in Self is the standard way to write modules out to disk as text files. Unlike Smalltalk, the Self standard world (the equivalent to a Smalltalk image) can be completely recreated from those text source files.
Since the source files are plain text and not a binary image, there isn't as much of a need for Self specific version control.
In short, use what you like to manage your .self files. The main distribution of Self stores its files in git on Github.
You will find yourself rebuilding your world from your source tree on a regular basis, for example if you rollback to a previous commit or add in a patch from a developer.