Add CHANGELOG

CHANGELOG.md

+# Changelog
+All notable changes to this project will be documented in this file.
+
+## [Unreleased]
+
+
+## [1.0.0] - 25th may 2020
+
+### Added
+ 
+* Complete workflow
+* snakemake rule system to handle rapidrun files
+
+### Changed
+
+* upgrade singularity to v3.6
+
+### Removed
+
+* marker.csv