title: How to downgrade rails version in Max OS X Snow Leopard?
body: <p>I have Mac OS X Snow leopard that has pre-installed Ruby 1.8.7 and Rails 3.0.1
  I need to work with Redmine a bit that requires Rails 2.3.5</p>
  
  <p>Is it possible to correctly downgrade my current rails 3.0.1 to rails 2.3.5?</p>