Add template for NodeJS

NodeJS is useful to make small standalone websockets apps. My app uses it for a realtime event pusher. This PR includes the skeleton to include a Node app in the subdir of your Rails project, and deploy it as a standalone.

You'll have to place the node app in a sub-folder of your Rails app, and specify the dir in `rubber_env.node.app_dir`

The init.d script is adapted from https://github.com/chovy/node-startup.