Documentation: sudo needed to do "npm install -g yange-forge"

[ramukima]

Works with "sudo" but not without it. May be the documentation can suggest that.

bash-3.2$ npm install -g yang-forge

yang-forge@1.0.2 prepublish /Users//yangify/yang-forge
coffee -o lib -c src

sh: coffee: command not found

npm ERR! addLocal Could not install /Users//yangify/yang-forge
npm ERR! Darwin 14.5.0
npm ERR! argv "/usr/local/Cellar/node/6.2.2/bin/node" "/usr/local/bin/npm" "install" "-g" "yang-forge"
npm ERR! node v6.2.2
npm ERR! npm v3.9.5
npm ERR! file sh
npm ERR! code ELIFECYCLE
npm ERR! errno ENOENT
npm ERR! syscall spawn
npm ERR! yang-forge@1.0.2 prepublish: coffee -o lib -c src
npm ERR! spawn ENOENT
npm ERR!
npm ERR! Failed at the yang-forge@1.0.2 prepublish script 'coffee -o lib -c src'.
npm ERR! Make sure you have the latest version of node.js and npm installed.
npm ERR! If you do, this is most likely a problem with the yang-forge package,
npm ERR! not with npm itself.
npm ERR! Tell the author that this fails on your system:
npm ERR! coffee -o lib -c src
npm ERR! You can get information on how to open an issue for this project with:
npm ERR! npm bugs yang-forge
npm ERR! Or if that isn't available, you can get their info via:
npm ERR! npm owner ls yang-forge
npm ERR! There is likely additional logging output above.

npm ERR! Please include the following file with any support request:
npm ERR! /Users//yangify/npm-debug.log