Ruby on rails and Node.js

As Shripad said, I'd consider trying to build your app with Node by itself. Geddy will feel familiar (getting started anyway) if you have experience with Rails. Note: I do not have experience on a real world app with Geddy, but it is the best Rails-like framework I've seen so far. For persistence you can use SQLite, PostgreSQL or CouchDB, just like you would with Rails. I thought about how to communicate between a Rails app and Node without any intermediary. In our work project we're using Redis as an intermediary between Rails and Node. Rails publishes messages to Redis, Node pulls messages from Redis. I could not find a good way or example projects to avoid the middle communication layer on a personal project, so I went with the same setup. The good news is Node Redis modules are written and once you get everything installed, it is easy to test out pushing messages back and forth.

If you are looking at creating real-time apps then go with node.js (high concurrency) alone. You really cannot integrate node.js into a rails app. You can however have a node server setup on another port with an api and websockets configured and then have your rails app communicate with that server. It is PITA to do that kind of setup. You rather build the entire web app in node itself. However, if you want anything rails specific that does not use juggernaut then i would suggest http://www.pusherapp.com.

Its extremely easy to setup server push using Pusher.

It already did. Not really NodeJs but a framework built on top if it. Yada, yada, yada... check this out: https://github.com/1602/express-on-railway