I've seen Github shows name instead of a linked username in commits and I realise that the right thing to do is to link by email. However, I already have a repository with a whole bunch of commits whose email is "none@none".
On BitBucket, I can specify a per-project mapping of committer name to BitBucket account, and this has worked well enough. Is there anything like this on GitHub?
If not, what other options are there, short of leaving the commits unlinked and rewriting the entire history?