Oops, you're right. That's actually a new bug, and has now been fixed.
As far as the transition goes, that's a great candidate for a blog post, but it's not as good a fit for a book. Plus, experience shows that starting from scratch often takes less time in the end.
Fair enough. My current plan when I've finished is to rewrite my collaborative blogging platform in Ruby (was Google App Engine + Python). It's got enough similarities to a twitter clone that I can base a lot of the infrastructure on railstutorial, but enough differences that I will definitely start from scratch rather than trying to modify the codebase. I guess I should move to rails 3.2 at the same time, and whizz through your new version in parallel.
As far as the transition goes, that's a great candidate for a blog post, but it's not as good a fit for a book. Plus, experience shows that starting from scratch often takes less time in the end.