Agile Web Development with Rails, Third Edition,Digital Beta

Information
About Rails Versions
This book is written for Rails 2. As this printing of the book is going to press,the current generally available Gem version of Rails is 2.1. The code in this
book has been tested against this version.
This book started life with the same text as the Second Edition, which covered Rails 1.2.6. Pages containing this original text have a gray heading and
footer. As we migrate content to Rails 2, you’ll find the header color changes to red. The Third Edition preface contains a table summarizing the status
of this update process. In particular, note that in many of the chapters the screenshots have not yet been updated to match the results produced by
Rails 2.1.
The Rails core team is continuing to work on Rails 2. From time to time, new releases may introduce incompatibilities for applications written for prior
versions of Rails. In order to experiment with these changes, the Rails developers are making the changes available via Edge Rails (discussed starting on
page 244). These changes won’t affect you unless you explicitly install this experimental code—you won’t find yourself running it unless you overide
Gem defaults or deliberately choose to use Edge Rails. However, if you do decide to run this experimental Rails code, you’ll find that some stuff in this
book (and some stuff in your existing Rails applications) may no longer run. To determine the version of Rails that you are running, you can issue rails -
at a command prompt.