private void pushExtensionsToDevice(AndroidDevice device, String extensionFile) {
    if (extensionFile != null) {
      String externalStorageDirectory = device.getExternalStoragePath();
      String deviceDexPath = new File(externalStorageDirectory, "extension.dex").getAbsolutePath();
      device.runAdbCommand(String.format("push %s %s", extensionFile, deviceDexPath));
    }
  }
This function will sign an android app and add it to the App Store. The function is made public because it also be
invoked by the Folder Monitor each time a new application dropped into this folder.

@param file
         - The file to be added to the app store
@throws AndroidSdkException
selendroid-standalone/src/main/java/io/selendroid/standalone/server/model/SelendroidStandaloneDriver.java