Updated README.md to match ember:bootstrap output

I'm new to this gem (and to Ember) and just noticed an inconsistency between the readme and the result of the `ember:bootstrap` output. Specifically, the includes that the generator adds to `application.js` didn't match what I was seeing, so I updated the doc. I hope this looks right, but understand you might already be working toward a rewrite that encompasses this change.

Thanks for the great project!

Cheers,
Andy