I used expect a while back to write a small bash script that logs into my server via ssh and pulls the latest commit from Github. I have this set to run on an Alfred command 'deploy site name'.

This is much more secure, in my opinion, than using a webhook to deploy new commits.

You may have to tweak it a bit to get it working with your specific ssh agent forwarding and ssh keys by only by deleting a few lines, but it works out of the box without those features.

https://gist.github.com/srcoley/3299526