development.rb

config.after_initialize do
  [User, And, All, The, Models, You, Want].each do |model|
    model.class_eval do
      include FakeActiveRecord3Methods
    end
  end
end

fake_active_record3_methods.rb

module FakeActiveRecord3Methods
  def self.included(base)
    base.class_eval do
      %w/select group order limit offset joins having/.each do |method|
        named_scope method.to_sym, lambda { |arg| { method.to_sym => arg } }
      end
      
      named_scope :where, lambda { |arg| { :conditions => arg } }
      named_scope :includes, lambda { |arg| { :include => arg } }
    end
  end
end