Update Readme description for standalone application

Revises Option 2 in the Readme to tighten up the recommendation a bit.  Instead of recommending a fork of a fork with stuff in it that's not needed, I think we should leave it up to the user to create a bare bones repo to push up as a separate app to Heroku.  At least until I get the chance to setup a Heroku button to do this a more streamlined fashion.  This should help to reduce some confusion people are having with Option 2.