Update CHANGELOG.md

Author: deniszh

CHANGELOG.md

@@ -1,5 +1,7 @@
 # Changelog
-All notable changes to this project will be documented in this file.
+All notable changes to upstream repo will be documented in this file.
+
+Please check [CHANGELOG_FORK.md](CHANGELOG_FORK.md) for specific changes added by `go-graphite` project members' to this repo. 
 
 The format is based on [Keep a Changelog](http://keepachangelog.com/en/1.0.0/)
 and this project adheres to [Semantic Versioning](http://semver.org/spec/v2.0.0.html).