GitHub seems pretty slow for me this morning
A quick look at status.github.com shows a spike for time to first byte. So don't worry if you're having issues. It's not just you.
Might be showing signs of recovery though. Build failures are down. But that could be because there are no builds now!
Hopefully just a blip.
Edit:
We are investigating reports of connectivity problems.
https://twitter.com/githubstatus/status/636110568911409152