title: "bin/rails: No such file or directory" w/ Ruby 2 & Rails 4 on Heroku
body: <p>While following the Rails 4 <strong>Beta</strong> version of Michael Hartl's <em><a href="http://ruby.railstutorial.org/ruby-on-rails-tutorial-book?version=4.0#top" rel="noreferrer">Ruby on Rails Tutorial</a></em>, my app fails to start on Heroku, but runs fine locally with <code>bundle exec rails server</code>.  Checking <code>heroku logs -t</code> reveals the following error:</p>
  
  <pre><code>$ heroku[web.1]: State changed from crashed to starting
  $ heroku[web.1]: Starting process with command `bin/rails server 
  -p 33847 -e $RAILS_ENV`
  $ app[web.1]: bash: bin/rails: No such file or directory
  $ heroku[web.1]: Process exited with status 127
  $ heroku[web.1]: State changed from starting to crashed
  $ heroku[web.1]: Error R99 (Platform error) -&gt; Failed to launch the 
  dyno within 10 seconds
  $ heroku[web.1]: Stopping process with SIGKILL
  </code></pre>
  
  <p>If I <code>heroku run bash</code> and check the <code>bin</code> directory, I can see that there is <strong>not</strong> a <code>rails</code> executable:</p>
  
  <pre><code>~$ ls bin
  erb  gem  irb  node rdoc  ri  ruby  testrb
  </code></pre>
  
  <p>What have I done wrong?  I followed the tutorial exactly.</p>