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+# Changelog
+All notable changes to this project will be documented in this file.
+
+The format is based on [Keep a Changelog][], and this project adheres to
+[Semantic Versioning][].
+
+## [Unreleased]
+
+## [Version 4.0.0]
+### Added
+- [x] rubocop rails and perf gems
+- [x] ruby version file
+### Changed
+- [x] rubocop version to 1.32.0
+- [x] rubocop-performance to 1.14.3
+- [x] rubocop-rails to 2.15.2
+### Removed
+- [x] rails 4 target
+
+  [Keep a Changelog]: https://keepachangelog.com/en/1.0.0/
+  [Semantic Versioning]: https://semver.org/spec/v2.0.0.html