title: store Array in sharedpreferences
body: <p>I have an <code>Array</code> with integer values. It will grow over time. It will have approximately up to 50 values.
  I want to store the array persistent and thus I thought about storing it in <code>SharedPreferences</code>.
  I know that no complex types can be stored in it, but I also heard about to serialise the <code>Array</code> and then store it in <code>SharedPreferences</code>.
  Can someone give me a hint or even better sample code how to do that?</p>