acts as tree in rails 3

I am facing problem with acts_as_tree_on_steroids with rails 3. Is there any plugin which will help in rails 3 same as acts as tree

app/controllers/question_attributes_controller.rb:9:in `index'

Rendered /usr/local/lib/ruby/gems/1.9.1/gems/actionpack-3.0.3/lib/action_dispatch/middleware/templates/rescues/_trace.erb (0.8ms) Rendered /usr/local/lib/ruby/gems/1.9.1/gems/actionpack-3.0.3/lib/action_dispatch/middleware/templates/开发者_StackOverflowrescues/_request_and_response.erb (6.5ms) Rendered /usr/local/lib/ruby/gems/1.9.1/gems/actionpack-3.0.3/lib/action_dispatch/middleware/templates/rescues/diagnostics.erb within rescues/layout for a.descendants

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use this instead http://rubygems.org/gems/acts_as_tree_rails3