Update changelog

Author: Teppo Koivula

CHANGELOG.md

@@ -7,6 +7,11 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ## [Unreleased]
 
+## [1.0.0] - 2019-06-29
+
+### Added
+- More in-depth introduction and instructions for developers and module / site profile authors to README.
+
 ## [0.1.0] - 2019-06-22
 
 ### Changed