RailRoad is a very good class diagram generator for Ruby on Rails applications.

Roy Wright modified it to support the state machine AASM.

Following you see an example of a model diagram, generated by
railroad -Mt | neato -Tpng > models_default.png

This is very great, but in bigger projects, I wanted to see the magic fields like id, user_id, post_id,…

Therefore, I modified the gem by adding an additional parameter  --show-magic to show the magic fields.

railroad -Mt --show-magic | neato -Tpng > models_with_magics.png creates the following diagram

The plugin can be installed via gemcutter.org
gem install dmattes-railroad_xing

Source is available on Github: http://github.com/dmattes/railroad_xing

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