update CHANGELOG for 1.4.0 release

CHANGELOG.md

@@ -1,6 +1,16 @@
 # Changelog
 
-## unreleased
+## v1.4.0 [2017-12-08]
+
+The v1.4.0 release has many new features, here is a list of some of the highlights:
+
+1. Load TICKscripts and alert handlers from a directory.
+2. Structed Logging  with a logging API endpoints to be able to tail logs for given tasks.
+3. Autoscale support for Docker Swarm and EC2 Autoscaling.
+4. Sideload data into your TICKscript streams from external sources.
+5. Fully customizable POST body for the alert POST handler and the httpPost node.
+
+See the complete list of bug fixes and features below.
 
 ### Bugfixes
 
@@ -28,6 +38,7 @@
 ## v1.4.0-rc1 [2017-11-09]
 
 ### Features
+
 - [#1408](https://github.com/influxdata/kapacitor/issues/1408): Add Previous state
 - [#1575](https://github.com/influxdata/kapacitor/issues/1575): Add support to persist replay status after it finishes.
 - [#1461](https://github.com/influxdata/kapacitor/issues/1461): alert.post and https_post timeouts needed.