Document loading ember application on specific controller/view/page of legacy rails project

The SPA (Single Page Application) all or nothing approach seems a little problematic. Especially for legacy rails apps that just want to get started with using ember in part of their application. Would be nice to provide users with a gentle way to dip their toe into ember development.

To this end it would be helpful to create a generator and/or better document how to use the `rootElement` property inside projects. And provide convenient mechanism/pattern to load ember project code in a specific part of a larger rails application.

Here is a high level gist

https://gist.github.com/eccegordo/7277817

If this was a generator it might also dovetail well with the pattern of creating multiple ember applications within a largish rails project.

I will post a stripped down example app, as soon as I can.