Add changelog to README

README.md

@@ -188,4 +188,14 @@ Emitted when a task has been delayed because of the `interval` rate-limit. Note
 
 #### 'concurrencyReached:$type'
 
-Emitted when a task has been queued up because of the `concurrency` limit. Can be useful to detect when your queue is backing up.
+Emitted when a task has been queued up because of the `concurrency` limit. Can be useful to detect when your queue is backing up.
+
+## Changelog
+
+* __1.2.0:__ Various changes:
+	* Added `awaitCompleted` and `drain` methods, and `queueCompleted` event.
+	* Fixed the `awaitDrained` Promise never resolving.
+	* Added debugging statements in the code.
+* __1.1.1:__ Fixed typo in the example; unit in the API rate limit should've been 'per minute', not 'per second'.
+* __1.1.0:__ Added `awaitDrained` method.
+* __1.0.0:__ Initial release.