append_features

# File activesupport/lib/active_support/dependencies.rb, line 176
      def self.append_features(base)
        base.class_eval do
          # Emulate #exclude via an ivar
          return if defined?(@_const_missing) && @_const_missing
          @_const_missing = instance_method(:const_missing)
          remove_method(:const_missing)
        end
        super
      end