class ActiveRecord::Associations::Builder::HasAndBelongsToMany

def build
  reflection = super
  define_destroy_hook
  reflection
end

def define_destroy_hook
  name = self.name
  model.send(:include, Module.new {
    class_eval <<-RUBY, __FILE__, __LINE__ + 1
      def destroy_associations
        association(:#{name}).delete_all
        super
      end
    RUBY
  })
end

def macro
  :has_and_belongs_to_many
end

def show_deprecation_warnings
  super
  [:delete_sql, :insert_sql].each do |name|
    if options.include? name
      ActiveSupport::Deprecation.warn("The :#{name} association option is deprecated. Please find an alternative (such as using has_many :through).")
    end
  end
end

def valid_options
  super + [:join_table, :association_foreign_key, :delete_sql, :insert_sql]
end