reset_counters

# File activerecord/lib/active_record/counter_cache.rb, line 20
      def reset_counters(id, *counters)
        object = find(id)
        counters.each do |association|
          has_many_association = reflect_on_association(association.to_sym)
          raise ArgumentError, "'#{self.name}' has no association called '#{association}'" unless has_many_association

          if has_many_association.is_a? ActiveRecord::Reflection::ThroughReflection
            has_many_association = has_many_association.through_reflection
          end

          foreign_key  = has_many_association.foreign_key.to_s
          child_class  = has_many_association.klass
          belongs_to   = child_class.reflect_on_all_associations(:belongs_to)
          reflection   = belongs_to.find { |e| e.foreign_key.to_s == foreign_key && e.options[:counter_cache].present? }
          counter_name = reflection.counter_cache_column

          stmt = unscoped.where(arel_table[primary_key].eq(object.id)).arel.compile_update({
            arel_table[counter_name] => object.send(association).count
          })
          connection.update stmt
        end
        return true
      end