I just deleted and recloned my Rails app. I've been using ruby-clean-css for CSS minification for a while now and it's all been great, but now all of a sudden I'm getting this: ``` % bundle exec rake assets:precompile RAILS_ENV=production rake aborted! NoMethodError: undefined method `new' for #<RubyCleanCSS::Compressor:0x00000 812414de8 @js_options={}> /home/example/vendor/bundle/ruby/2.2.0/gems/sprockets-3.2.0/lib/sprockets/ legacy_tilt_processor.rb:25:in `call' /home/example/vendor/bundle/ruby/2.2.0/gems/sprockets-3.2.0/lib/sprockets/ processor_utils.rb:75:in `call_processor' /home/example/vendor/bundle/ruby/2.2.0/gems/sprockets-3.2.0/lib/sprockets/ processor_utils.rb:57:in `block in call_processors' /home/example/vendor/bundle/ruby/2.2.0/gems/sprockets-3.2.0/lib/sprockets/ processor_utils.rb:56:in `reverse_each' /home/example/vendor/bundle/ruby/2.2.0/gems/sprockets-3.2.0/lib/sprockets/ processor_utils.rb:56:in `call_processors' /home/example/vendor/bundle/ruby/2.2.0/gems/sprockets-3.2.0/lib/sprockets/ loader.rb:86:in `load_asset_by_uri' /home/example/vendor/bundle/ruby/2.2.0/gems/sprockets-3.2.0/lib/sprockets/ loader.rb:45:in `block in load' /home/example/vendor/bundle/ruby/2.2.0/gems/sprockets-3.2.0/lib/sprockets/ loader.rb:155:in `fetch_asset_from_dependency_cache' /home/example/vendor/bundle/ruby/2.2.0/gems/sprockets-3.2.0/lib/sprockets/ loader.rb:38:in `load' /home/example/vendor/bundle/ruby/2.2.0/gems/sprockets-3.2.0/lib/sprockets/ cached_environment.rb:20:in `block in initialize' /home/example/vendor/bundle/ruby/2.2.0/gems/sprockets-3.2.0/lib/sprockets/ cached_environment.rb:47:in `yield' /home/example/vendor/bundle/ruby/2.2.0/gems/sprockets-3.2.0/lib/sprockets/ cached_environment.rb:47:in `load' /home/example/vendor/bundle/ruby/2.2.0/gems/sprockets-3.2.0/lib/sprockets/ base.rb:63:in `find_asset' /home/example/vendor/bundle/ruby/2.2.0/gems/sprockets-3.2.0/lib/sprockets/ base.rb:70:in `find_all_linked_assets' /home/example/vendor/bundle/ruby/2.2.0/gems/sprockets-3.2.0/lib/sprockets/ manifest.rb:130:in `block in find' /home/example/vendor/bundle/ruby/2.2.0/gems/sprockets-3.2.0/lib/sprockets/ manifest.rb:129:in `each' /home/example/vendor/bundle/ruby/2.2.0/gems/sprockets-3.2.0/lib/sprockets/ manifest.rb:129:in `find' /home/example/vendor/bundle/ruby/2.2.0/gems/sprockets-3.2.0/lib/sprockets/ manifest.rb:162:in `compile' /home/example/vendor/bundle/ruby/2.2.0/gems/sprockets-rails-2.3.1/lib/spro ckets/rails/task.rb:70:in `block (3 levels) in define' /home/example/vendor/bundle/ruby/2.2.0/gems/sprockets-3.2.0/lib/rake/sproc ketstask.rb:147:in `with_logger' /home/example/vendor/bundle/ruby/2.2.0/gems/sprockets-rails-2.3.1/lib/spro ckets/rails/task.rb:69:in `block (2 levels) in define' Tasks: TOP => assets:precompile (See full trace by running task with --trace) ``` **environments/production.rb** ``` config.assets.css_compressor = :cleancss ``` **Gemfile** ``` gem "ruby-clean-css" ```