Add link to PWA instructions to main README

Author: gaearon

README.md

@@ -120,6 +120,7 @@ The [User Guide](https://github.com/facebookincubator/create-react-app/blob/mast
 - [Generating Dynamic `<meta>` Tags on the Server](https://github.com/facebookincubator/create-react-app/blob/master/packages/react-scripts/template/README.md#generating-dynamic-meta-tags-on-the-server)
 - [Running Tests](https://github.com/facebookincubator/create-react-app/blob/master/packages/react-scripts/template/README.md#running-tests)
 - [Developing Components in Isolation](https://github.com/facebookincubator/create-react-app/blob/master/packages/react-scripts/template/README.md#developing-components-in-isolation)
+- [Making a Progressive Web App](https://github.com/facebookincubator/create-react-app/blob/master/packages/react-scripts/template/README.md#making-a-progressive-web-app)
 - [Deployment](https://github.com/facebookincubator/create-react-app/blob/master/packages/react-scripts/template/README.md#deployment)
 - [Troubleshooting](https://github.com/facebookincubator/create-react-app/blob/master/packages/react-scripts/template/README.md#troubleshooting)