Adds Ember to Gemfile

* And removes chosen-rails
Runs JS Ember script for initial directories and files
Adds vendor assets for development and production Ember
Adds serializers directory
Creates a "Hello World" ember app
Updates the README
Updates found_user for Ember tut
Includes some sample scorecards
Fixes deprecation error
Rewrites application layout in emblem
Merge pull request #12 from gschorkopf/ember

Ember