UML diagram for basic Rails classes

Where I can find UML for RoR itself? with ActiveRecord etc classes. If there is no one, advise me how to make it faster and better. I just should read sources or some o开发者_运维知识库ther thing?

not sure for ROR itself but you can check RailsRoad for generating your app's UML

If your app is Rails 3, use the RailsRoady gem instead. You can find it here.