Building for Chrome
Updated Feb 2013
Log in to the Chrome Web Store and upload a zip of the App ID Sanity.safariextension directory. It's no longer necessary to build and sign a .crx.
Old instructions (now outdated)
Add a chrome alias for a tidier command line
alias chrome="/Applications/Google\ Chrome.app/Contents/MacOS/Google\ Chrome"
Then build thus:
chrome --pack-extension=./App\ ID\ Sanity.safariextension/ \ --pack-extension-key=/Users/simon/Library/Keys/uk.co.goosoftware.app-id-sanity.chrome.pem