Tóm tắt nội dung: 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 cov-ered 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...