Gitbridge seems to be unable to handle X-Forward Headers that allow it to run behind a proxy for ssl offloading and github authentication.
Setting the "ProxyPreserveHost On" corrects the domain name that gitbridge thinks it's running on. However, gitbridge changes the protocol from https, to http.
Further editing the location header to change the response's query to https lets github authenticate, but gitbrige then complains that the JWT token isn't valid. Likely because the protocols don't match what gitbridge originally sent.