title: Permissions error when using gem to install Rails via RVM
body: <p>I'm trying to install Rails using Rubygems via RVM. When running the command <code>gem install rails -v 3.2.0</code>, I receive the error:</p>
  
  <pre><code>ERROR: While executing gem ... (Gem::FilePermissionError)
  You don't have write permissions into the /usr/share/ruby-rvm/gems/ruby-1.9.3-p0 directory.
  </code></pre>
  
  <p>I don't want to run it with <code>sudo</code> because RVM's website specifically advises against that. Any thoughts why I may be getting this error and how to get around it?</p>
  
  <p>Details:</p>
  
  <ul>
  <li>RVM version 1.10.2</li>
  <li>Ruby version 1.9.3</li>
  <li>Ubuntu version 11.10</li>
  </ul>