title: How to have multiple versions of Ruby AND Rails, and their combinations on Windows?
body: <p>Since Windows doesn't support rvm (Ruby version Manager), how do we have</p>
  
  <ul>
  <li>Ruby 1.8.7, Rails 2.3.8  </li>
  <li>Ruby 1.8.7, Rails 3.0.0  </li>
  <li>Ruby 1.9.2, Rails 3.0.0</li>
  </ul>
  
  <p>on the same PC?  Virtual machines can be used but it is kind of troublesome.</p>