update changelog

Author: urkle

CHANGELOG.md

@@ -4,6 +4,10 @@ All notable changes to this project will be documented in this file.
 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)
 
+## [upcoming]
+### Changed
+- dropped ruby 2.4 support
+
 ## [0.5.1]
 ### Fixed
 - corrected licenses
@@ -23,4 +27,3 @@ and this project adheres to [Semantic Versioning](http://semver.org/spec/v2.0.0.
 ## [0.4.1]
 ### Added
 - Added support for database aliases ( PR #26 )
-