DOC: add CHANGELOG file

CHANGELOG.md

+# CHANGELOG
+
+All notable changes to this project will be documented in this file.
+
+The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
+and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
+
+
+## v2.0.0
+
+### Changed
+- #11 - Use VM NAT connection instead of bridge
+
+### Added
+- Add helping message to show after vagrant up
+- add CODE_OF_CONDUCT file
+- add CHANGELOG file
+
+
+## v1.0.0
+
+First release