I believe that what you need to do is add something like this to the Info.plist file and give a short description why your app needs that permission. That piece of text should show up when your application makes the request to use the device's motion sensor.
<key>NSMotionUsageDescription</key>
<string>Example: You should fill this in</string>
I don't have an iOS device myself to try this out, so you should try it out on a real device before submitting again.