def make_slave!(node)
      perform_operation do |redis|
        unless slave_of?(node)
          redis.slaveof(node.host, node.port)
          logger.info("#{self} is now a slave of #{node}")
          wakeup
        end
      end
    end
def make_slave!(node)
      perform_operation do |redis|
        unless slave_of?(node)
          redis.slaveof(node.host, node.port)
          logger.info("#{self} is now a slave of #{node}")
          wakeup
        end
      end
    end
Makes this node a slave of the given node.

 @param [Node] node the node of which to become a slave