Add link to nvm-windows (facebook#3489)

Author: davidgilbertson

README.md

@@ -40,7 +40,7 @@ Install it once globally:
 npm install -g create-react-app
 ```
 
-**You’ll need to have Node >= 6 on your machine**. You can use [nvm](https://github.com/creationix/nvm#installation) to easily switch Node versions between different projects.
+**You’ll need to have Node >= 6 on your machine**. You can use [nvm](https://github.com/creationix/nvm#installation) (macOS/Linux) or [nvm-windows](https://github.com/coreybutler/nvm-windows#node-version-manager-nvm-for-windows) to easily switch Node versions between different projects.
 
 **This tool doesn’t assume a Node backend**. The Node installation is only required for Create React App itself.