Updating adb instructions.

Author: anp

react-native-scripts/template/README.md

@@ -55,11 +55,19 @@ Like `npm start`, but also attempts to open your app in the iOS Simulator if you
 
 #### `npm run android`
 
-Like `npm start`, but also attempts to open your app on a connected Android device or emulator. Requires an installation of Android build tools (see [React Native docs](https://facebook.github.io/react-native/docs/getting-started.html) for detailed setup). We also recommend installing Genymotion as your Android emulator. Once you've finished setting up the native build environment:
+Like `npm start`, but also attempts to open your app on a connected Android device or emulator. Requires an installation of Android build tools (see [React Native docs](https://facebook.github.io/react-native/docs/getting-started.html) for detailed setup). We also recommend installing Genymotion as your Android emulator. Once you've finished setting up the native build environment, there are two options for making the right copy of `adb` available to Create React Native App:
+
+##### Using Android Studio's `adb`
 
 1. Make sure that you can run adb from your terminal.
 2. Open Genymotion and navigate to `Settings -> ADB`. Select “Use custom Android SDK tools” and update with your [Android SDK directory](https://stackoverflow.com/questions/25176594/android-sdk-location).
 
+##### Using Genymotion's `adb`
+
+1. Find Genymotion’s copy of adb. On macOS for example, this is normally `/Applications/Genymotion.app/Contents/MacOS/tools/`.
+2. Add the Genymotion tools directory to your path (instructions for [Mac](http://osxdaily.com/2014/08/14/add-new-path-to-path-command-line/), [Linux](http://www.computerhope.com/issues/ch001647.htm), and [Windows](https://www.howtogeek.com/118594/how-to-edit-your-system-path-for-easy-command-line-access/)).
+3. Make sure that you can run adb from your terminal.
+
 #### `npm run eject`
 
 This will start the process of "ejecting" from Create React Native App's build scripts. You'll be asked a couple of questions about how you'd like to build your project.