title: Rails 3, MongoId & bson version problem
body: <p>I just updated to Rails 3 final. Now I'm having problems with MongoId, Mongo's Ruby driver &amp; bson. When I try to run Rails, I get "You have already activated bson 1.0.7, but your Gemfile requires bson 1.0.4. Consider using bundle exec. (Gem::LoadError)".</p>
  
  <p>MongoId requires bson_ext 1.0.4 so I have gem "bson_ext", "1.0.4" in my Gemfile. I tried to uninstall bson 1.0.7 but then Rails failed to start because Mongo Ruby driver requires bson >= 1.0.5.</p>
  
  <p>So any ideas how I can get this solved?</p>