cch1

module ActiveRecord
  class Reflection::AssociationReflection
    # Return a named scope instead of the bare ActiveRecord::Base subclass.
    def klass_with_scope
      k = klass_without_scope
      options[:scope].nil? ? k : k.send(options[:scope])
    end
    alias_method_chain :klass, :scope
  end

cch1

diff --git a/activerecord/lib/active_record/associations.rb b/activerecord/lib/active_record/associations.rb
index 7f78191..e55b639 100755
--- a/activerecord/lib/active_record/associations.rb
+++ b/activerecord/lib/active_record/associations.rb
@@ -1557,7 +1557,8 @@ module ActiveRecord
           :finder_sql, :counter_sql,
           :before_add, :after_add, :before_remove, :after_remove,
           :extend, :readonly,
-          :validate
+          :validate,

cch1

class Tag
  has_many :taggings
end

class Tagging
  belongs_to :tag
  belongs_to :posts
  
  # uses a string 'flag' column but could be changed to a boolean important 
  # column later, hence the need to encapsulate!