Update README.md

Author: WellJay

distributedLock/README.md

@@ -1,4 +1,6 @@
 - `RedisLockTool.tryGetDistributedLock();` GET LOCK  key = caller className&method   value = Current Thread Id
 - `RedisLockTool.tryGetDistributedLock(String lockKey, String requestId);` GET LOCK
 - `RedisLockTool.tryGetDistributedLock(String lockKey, String requestId, Integer expireSecond);`
-- `RedisLockTool.tryGetDistributedLock(String lockKey, String requestId, Integer expireSecond, Long loopTimes, Long sleepInterval);`
+- `RedisLockTool.tryGetDistributedLock(String lockKey, String requestId, Integer expireSecond, Long loopTimes, Long sleepInterval);`  
+  
+redis集群情况下推荐[RedLock](https://github.com/redisson/redisson)