500 on first attempt #4

Thanks so much for creating this!

I just went through the signup flow, but hit a 500 error after I'd installed the GitHub app and authenticated with my ATproto account.

I think this is probably because I installed the GH app for all my repos, and there are some private ones in there? At least I managed to resolve the issue by uninstalling the app, and then re-installing but only in a select few (public) repos.