Migration Issue

You need to update to Rails 1.2 RC 1. Since the book relies on edge,
that's where you can fix your issue.

gem install rails --source http://gems.rubyonrails.org
--include-dependencies

is the code to run

For more info:
http://weblog.rubyonrails.org/2006/11/23/rails-1-2-release-candidate-1