code: function RedisCluster(serversConfig, redisFactory, keyMapper) {
  	this.keyMapper = keyMapper
  	this.servers = {}
  	this.redisFactory = redisFactory
  
  	for (var i = 0; i < serversConfig.length; i++) {
  		this.addServer(serversConfig[i].host, serversConfig[i].port)	
  	}
  }
docs: /*
  The redis cluster helps write and read redis key/values from several redis instances.
  
  @param serversConfig 	- an array of redis server objects, e.g [{ port: 6379, host: '127.0.0.1' }, { port: 6379, host: '192.168.56.1' }]
  
  @param redisFactory 	- a factory that returns a redis client in response to calling factory.createClient(port, ip),
  usually this will just be redis (require('redis'))
  
  @param keyMapper		- maps keys to redis servers, the keyMapper must respect this interface:
  
  serverString getNode(key)
  serverString addServer(server)