The free download offer was for an advance edition of the book. The free offer expired in November 2013 (!).
The book has been updated for Rails 4.1 and it is available (with a number of other tutorials) from the RailsApps project:
only as part of a monthly subscription.
I’m sorry that it’s not obvious that the download offer was for a limited duration in November 2013. The title of the email announcement “free today” refers to the day the email announcement was sent to this Google Group. In retrospect, I should have said “free on November 27, 2013.” Sorry if anyone is disappointed.
– Daniel Kehoe, author of ‘Learn Ruby on Rails’