Rails 3.1 rc1 and Carrierwave broken

when I use Rails 3.1 rc1 with Carrierwave (master / git / 0.5.4), rails server 开发者_StackOverflow社区won't start. I get the following error:

/Library/Ruby/Gems/1.8/gems/activerecord-3.1.0.rc1/lib/active_record/base.rb:1073:in `method_missing': undefined method `mount_uploader' for #<Class> (NoMethodError)

Any Idea how to fix that?

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Looks like the Carrierwave gem is not loaded? Check your gem file and don't forget to do:

bundle install