Depend on edge version of sass-rails

railties/lib/rails/generators/rails/app/templates/Gemfile

@@ -10,7 +10,7 @@ source 'http://rubygems.org'
 # Gems used only for assets and not required
 # in production environments by default.
 group :assets do
-  gem 'sass-rails'
+  gem 'sass-rails', :git => 'git://github.com/rails/sass-rails'
   gem 'coffee-rails', :git => 'git://github.com/rails/coffee-rails'
   gem 'uglifier'
 end