When creating a USERNAME.pub file with a public key and adding USERNAME to the config file, is the USERNAME string arbitrary (I can name my gitosis users how I like), or determined by something like the SSH key?
Gitosis tutorials give examples of how to add users to a repo which are very clear (eg http://scie.nti.st/2007/11/14/hosting-git-repositories-the-easy-and-secure-way) but they don't explain this point.