Added Changelog.md file.

Author: srtab

CHANGELOG.md

@@ -0,0 +1,16 @@
+# Changelog
+All notable changes to this project will be documented in this file.
+
+The format is based on [Keep a Changelog](http://keepachangelog.com/)
+and this project adheres to [Semantic Versioning](http://semver.org/).
+
+## [1.0.0] - 2017-12-07
+ - First release;
+
+## [1.0.1] - 2017-12-07
+### Added
+ - Added CHANGELOG.md file.
+
+### Fixed
+ - Fix formatValue method on ChoiceWidget when value is empty or null;
+ - Fix validate on ChoiceField when value if empty and not required.