title: Managing multiple versions of a Ruby Gem
body: <p>I'm a newbie, but I have a question regarding managing different versions of a gem, in my case, zurb-foundation.  A new version just came out and I did a gem update and it made my older versions of the framework no longer compile.  </p>
  
  <p>My project contains a config.rb file that starts with</p>
  
  <pre><code>require 'zurb-foundation'
  </code></pre>
  
  <p>How does Ruby know to use the latest version of this?  Is there a symlink somewhere pointing to the latest version?  If so, I was thinking I could just re-write this symlink depending on which project I'm currently working in.</p>