Rails 3.1: Release candidate

I am using Jammit for asset management and Barista for compiling coffeescript on the fly with a Rails 3.0.7 project.<p>Any comparisons between Jammit and Sprocket will be welcome.

Kudos for bundling a simple BCrypt-based authentication.

Notice this in the new rake 0.9.0:<p>* <i>Incompatible</i> <i>change</i>: Rake DSL commands ('task', 'file', etc.) are no longer private methods in Object. If you need to call 'task :xzy' inside your class, include Rake::DSL into the class. The DSL is still available at the top level scope (via the top level object which extends Rake::DSL).<p><a href="http://github.com/jimweirich/rake/blob/master/CHANGES" rel="nofollow">http://github.com/jimweirich/rake/blob/master/CHANGES</a>

Anybody know how easy it will be to upgrade a 3.0 Rails app to 3.1? Especially in regards to changing it to use jQuery.

Kind of a bummer that "HTTP streaming" only works with Ruby 1.9.2. I'm not against upgrading to Ruby 1.9.2, it's just that Puppet doesn't support it yet.

Will this make all my latest Rails 3.0 books worthless?