Add dev docs for setting up Precious

Author: kevcenteno

README.dev.md

@@ -17,6 +17,7 @@
 11. Verify the release on
     [NPM](https://npmjs.com/package/@maxmind/geoip2-node).
 
-## Set up pre-commit hooks
+## Set up Precious to tidy and lint
 
-`npm run setup` to install husky pre-commit hooks
+1. Run `mkdir -p local && ./bin/install-precious local` to set up Precious locally
+2. Run `./git/setup.sh` to set up pre-commit hook that invokes Precious