Add iOS setup link from Apache Cordova.

README.md

@@ -10,6 +10,7 @@ Debug your code, find commands in the Command Palette, and use IntelliSense to b
 1. Open a Terminal (on a Mac) or a Command Prompt (on a Windows computer).
 2. Run `npm install -g cordova`
 3. If you're planning on targeting iOS devices,
+ * Set up your machine by following instructions at [iOS Platform Guide from Apache Cordova](https://cordova.apache.org/docs/en/latest/guide/platforms/ios/index.html)
  * Install [HomeBrew](http://brew.sh/) on your Mac.
  * Open a Terminal and run `brew install ideviceinstaller ios-webkit-debug-proxy`
 4. If you're planning on targeting Android devices, set up your machine by following instructions at [Android Platform Guide from Apache Cordova](https://cordova.apache.org/docs/en/latest/guide/platforms/android/index.html)