title: How to resolve issue starting Ruby on Rails server on Cloud9 ide?
body: <p>I'm trying to start the web server for a rails app on a Cloud9 IDE workspace and I'm receiving this error message:</p>
  
  <blockquote>
    <p>`require': cannot load such file -- rack/handler/server (LoadError) </p>
  </blockquote>
  
  <p>This is the code that I am running: </p>
  
  <pre><code>rails s -p $PORT -b $IP server
  </code></pre>
  
  <p>I'm very new to Ruby on Rails so my apologies if this pretty simple.  </p>