Save the patch somewhere. If you’re using linux you can use curl:
curl -L https://github.com/JustinTulloss/zeromq.node/pull/47.patch > /tmp/47.patch
To apply the patch use git apply. You can see if the patch will apply cleanly with the check option. Change to your git directory and run:
git apply --check /tmp/47.patch
If it looks like you want to apply the patch remove the check option
git apply /tmp/47.patch