Add changelog and Testing info in Readme

Author: Willem Wigman

CHANGELOG.md

@@ -0,0 +1,15 @@
+# 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).
+
+## 1.0.0 - 2020-04-27
+### Added
+- Plugins for category, product and page layouts that allow custom layout files to be loaded with a global identifier
+ (`0`). E.g. `catalog_category_view_selectable_0_.xml` for Categories.
+
+## 1.1.0 - 2020-05-02
+### Added
+- Adds frontend test coverage for global custom layout updates
+- Fixes [#7](https://github.com/integer-net/magento2-global-custom-layout/issues/7) where layout handles were not merged in Product and Page Plugins' `afterFetchAvailableFiles()` method.

README.md

@@ -49,6 +49,23 @@ More info on default behaviour of selectable layouts:
 
 Zero configuration needed.
 
+## Change log
+
+Please see [CHANGELOG](CHANGELOG.md) for more information on what has changed recently.
+
+## Testing
+
+### Magento Integration Tests
+
+0. Configure test database in `dev/tests/integration/etc/install-config-mysql.php`. [Read more in the Magento docs.](https://devdocs.magento.com/guides/v2.3/test/integration/integration_test_execution.html) 
+
+1. Copy `Test/Integration/phpunit.xml.dist` from the package to `dev/tests/integration/phpunit.xml` in your Magento installation.
+
+2. In that directory, run
+    ``` bash
+    ../../../vendor/bin/phpunit
+    ```
+
 ## Contributing
 
 Please see [CONTRIBUTING](CONTRIBUTING.md) for details.