title: What's the deal with rubygems on Debian? It's different and strange
body: <p>I've noticed at least the following oddities around rubygems on Debian (5.0 lenny in my case):</p>
  
  <ul>
  <li>Packages go into a different installation location: /var/lib/gems vs /usr/lib/ruby/gems</li>
  <li>The debian package is rubygems 1.3.6, and updating rubygems to the latest version (1.3.7) doesn't work:</li>
  </ul>
  
  <pre>
    $ sudo gem update --system
    ERROR:  While executing gem ... (RuntimeError)
      gem update --system is disabled on Debian. RubyGems can be updated using the official Debian repositories by aptitude or apt-get.
  </pre>
  
  <ul>
  <li>Not all gems appear to work like they do on other systems. For instance, when installing Phusion Passenger, it did not detect the "rack" gem even though it was definitely installed.</li>
  <li>Manually installing rubygems using the source tarball and reinstalling all my gems (to /usr/lib/ruby/gems) made my problems go away.</li>
  </ul>
  
  <p>What's the deal? Why is debian's package different?</p>