Add README

Author: brentvatne

README.md

@@ -0,0 +1,13 @@
+# React Navigation website
+
+## Run it locally
+
+1. Clone the repository
+2. `cd` into the `website` directory.
+3. Run `yarn` (or `npm install`)
+4. `yarn start`
+
+## Make changes
+
+* The `docs` directory contains the markdown files used to generate the website. Change them and refresh the page when running the documentation locally and you will see the changes reflected.
+* If you want to add a new page, you need to add it to [sidebars.json](https://github.com/react-navigation/react-navigation.github.io/blob/source/website/sidebars.json) and then restart the server.