Recover Force Push on Github

gistfile1.txt

# First, you must get the previous commit sha, the one before the forced push:

## Hit through terminal
curl -u <username> https://api.github.com/repos/:owner/:repo/events

# Then you can create a branch from this sha:

## Hit through terminal
curl -u <github-username> -X POST -d '{"ref":"refs/heads/<new-branch-name>", "sha":"<sha-from-step-1>"}' https://api.github.com/repos/:owner/:repo/git/refs

#Finally, you can clone the repository locally, and force push again to master:
git clone repo@github
git checkout master
git reset --hard origin/<new-branch-name>
git push -f origin master

Credit: Sankara Rameswaran