def publish
      publisher.publish('instance', added: info) do |redis|
        redis.setex "instance_#{ @id }", Attention.options[:ttl], JSON.dump(info)
      end
      heartbeat
    end
def publish
      publisher.publish('instance', added: info) do |redis|
        redis.setex "instance_#{ @id }", Attention.options[:ttl], JSON.dump(info)
      end
      heartbeat
    end
Creates an Instance
 @param ip [String] Optionally override the IP of the server
 @param port [Fixnum, Numeric] Optionally specify the port of the server
 Publishes this server and starts the {#heartbeat}