Merge pull request #44 from zalando-incubator/feature/changelog

Changelog added to project.

Author: vadeg

CHANGELOG.MD

@@ -0,0 +1,20 @@
+# Changelog
+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).
+
+## [Unreleased]
+
+### Added
+- Changelog
+- Contribution guide
+
+### Changed
+- Updated to Java 8
+- Updated Spring version to `4.3.8.RELEASE`
+- Postgresql JDBC driver updated to version `42.1.1`
+- Project license changed to [MIT](LICENSE).
+
+### Removed
+- Java 7 support