Update README.md

Author: winterbe

README.md

@@ -8,6 +8,7 @@ This repository contains all code samples from the Java 8 related posts of my [b
 - [Java 8 Nashorn Tutorial](http://winterbe.com/posts/2014/04/05/java8-nashorn-tutorial/)
 - [Java 8 Concurrency Tutorial: Threads and Executors](http://winterbe.com/posts/2015/04/07/java8-concurrency-tutorial-thread-executor-examples/)
 - [Java 8 Concurrency Tutorial: Synchronization and Locks](http://winterbe.com/posts/2015/04/30/java8-concurrency-tutorial-synchronized-locks-examples/)
+- [Java 8 Concurrency Tutorial: Atomic Variables and ConcurrentMap](http://winterbe.com/posts/2015/05/22/java8-concurrency-tutorial-atomic-concurrent-map-examples/)
 - [Java 8 API by Example: Strings, Numbers, Math and Files](http://winterbe.com/posts/2015/03/25/java8-examples-string-number-math-files/)
 - [Avoid Null Checks in Java 8](http://winterbe.com/posts/2015/03/15/avoid-null-checks-in-java/)
 - [Fixing Java 8 Stream Gotchas with IntelliJ IDEA](http://winterbe.com/posts/2015/03/05/fixing-java-8-stream-gotchas-with-intellij-idea/)