def records_modified_since(time)
      condition = []
      %w(updated_at created_at).each do |col|
        condition << "#{col} >= ?" if column_names.include? col
      end
      if condition.empty?
        logger.warn "#{self.name}: Override records_modified_since(time) to keep the index up to date with records changed during rebuild."
        []
      else
        where([ condition.join(' AND '), *([time]*condition.size) ]).all
      end
    end
def records_modified_since(time)
      condition = []
      %w(updated_at created_at).each do |col|
        condition << "#{col} >= ?" if column_names.include? col
      end
      if condition.empty?
        logger.warn "#{self.name}: Override records_modified_since(time) to keep the index up to date with records changed during rebuild."
        []
      else
        where([ condition.join(' AND '), *([time]*condition.size) ]).all
      end
    end
Returns all records modified or created after the specified time.
 Used by the rake rebuild task to find models that need to be updated in
 the index after the rebuild finished because they changed while the
 rebuild was running.
 Override if your models don't stick to the created_at/updated_at
 convention.