How to use with git for signing commits and tags?

Github announced https://github.com/blog/2144-gpg-signature-verification today. Would be nice if there was a guide on the "help" section of the website for using keybase for such a thing.

From my understanding it works like so:
1. Add your keybase public key to github
2. Save your keybase private key to your computer somewhere, and add it to git via `git config --global user.signingkey /Users/YOU/.keys/keybase` where `/Users/YOU/.keys/keybase` is the private key location
3. Use `-S` flag with git commits and tags

Start by reviewing the requested help section of the Keybase website and the GitHub GPG signature announcement linked in the issue. Verify the described public-key, private-key, signing-key, and -S steps for commits and tags. Done means a clear guide is available in the help section and accurately explains this workflow.

Written by the indexing model from the issue text.