reverse_order

# File activerecord/lib/active_record/relation/query_methods.rb, line 137
    def reverse_order
      order_clause = arel.order_clauses.join(', ')
      relation = except(:order)

      order = order_clause.blank? ?
        "#{@klass.table_name}.#{@klass.primary_key} DESC" :
        reverse_sql_order(order_clause)

      relation.order(Arel.sql(order))
    end