Update CHANGELOG.md

CHANGELOG.md

@@ -6,6 +6,17 @@ 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
+- Development build now include instrumentation code, updated build scripts
+   - `npm run build` will build for development with instrumentation code
+   - `npm run prepublishOnly` will build for production
+   - `npm run watch` will also run Webpack in watch loop
+- Automated testing using visual regression testing technique
+   - [Docker-based](https://github.com/SeleniumHQ/docker-selenium) automated testing using headless Chrome and [Web Driver](https://npmjs.com/packages/selenium-webdriver)
+   - Screenshot comparison using [`jest-image-snapshot`](https://npmjs.com/packages/jest-image-snapshot) and [`pixelmatch`](https://npmjs.com/package/pixelmatch)
+   - Code is instrumented using [`istanbul`](https://npmjs.com/package/istanbul)
+   - Test report is hosted on [Coveralls](https://coveralls.io/github/compulim/BotFramework-WebChat)
+
 ### Changed
 - Bump dependencies, in [#1303](https://github.com/Microsoft/BotFramework-WebChat/pull/1303)
    - `@babel`