Update README.md

Author: rwieruch

README.md

@@ -1,6 +1,6 @@
 # The Road to Learn React - Hackernews Client
 
-[![Build Status](https://travis-ci.org/the-road-to-learn-react/hackernews-client.svg?branch=master)](https://travis-ci.org/the-road-to-learn-react/hackernews-client)
+[![Build Status](https://travis-ci.org/the-road-to-learn-react/hackernews-client.svg?branch=master)](https://travis-ci.org/the-road-to-learn-react/hackernews-client) [![Slack](https://slack-the-road-to-learn-react.wieruch.com/badge.svg)](https://slack-the-road-to-learn-react.wieruch.com/)
 
 The application you will build when you read the book to [learn React](https://www.robinwieruch.de/the-road-to-learn-react/).
 
@@ -13,4 +13,4 @@ The application you will build when you read the book to [learn React](https://w
 
 You can find the different chapter commits [in the releases](https://github.com/rwieruch/hackernews-client/releases) too.
 
-After reading the book, you can continue to [learn about Redux and MobX in React](https://roadtoreact.com/course-details?courseId=TAMING_THE_STATE) for state management.
+After reading the book, you can continue to [learn about Redux and MobX in React](https://roadtoreact.com/course-details?courseId=TAMING_THE_STATE) for state management.