Improve the demo experience

rails-app/bin/rake

@@ -0,0 +1,9 @@
+#!/usr/bin/env ruby
+begin
+  load File.expand_path('../spring', __FILE__)
+rescue LoadError => e
+  raise unless e.message.include?('spring')
+end
+require_relative '../config/boot'
+require 'rake'
+Rake.application.run