Update changelog

Author: darkriszty

CHANGELOG.md

@@ -5,6 +5,8 @@ All notable changes to the `markdowntableprettify` extension will be documented
 The format is based on [Keep a Changelog](http://keepachangelog.com/) and this project adheres to [Semantic Versioning](http://semver.org/).
 
 ## [Unreleased]
+### Added
+- Issue #15: Support alignment options
 
 ## 2.0.0 - 2012-02-09
 ### Added