Prerender: Let search engines crawl your JS apps
Prerender makes it possible for search engines to perfectly crawl your JavaScript apps. There are Node.js, PHP, and Ruby on Rails versions available, and it’s fairly simple and straightforward to use, with thorough documentation.

Prerender Service
This is a node server that uses phantomjs to render a javascript-rendered page as HTML. It should be used in conjunction with prerender_rails or prerender-node middleware to serve the rendered HTML to crawlers for SEO. You don't have to run this service on your own since I have it deployed on Heroku already. Get started in two lines of code using Rails or Node
It is also meant to be proxied through your server so that any relative links to things like CSS will work.
It is currently deployed at http://prerender.herokuapp.com, or you can deploy your own.