Update 2014-05-07-building-an-ember-app-with-rails-part-1.md

in ember-cli 0.2.8 at least,
 'ember new' doesn't appear to do anything

» ember --help                                                                                                                       ± develop:10918ee 22:57:53

  Usage: ember [command] [options]

  Command-Specific Help

    ember [command] --help

  Commands:

    create [options]       creates a new ember application at [dir]