title: ListProperty vs StringListProperty on Google App Engine
body: <p>I want to store lists of integers (user ids), should I make them strings and use a StringListProperty, or just use a ListProperty, I'm wondering what is more optimized, the specific StringListProperty of the heterogeneous ListProperty (when used with only Integers).</p>
  
  <p>I will need to add users to the list until it reaches a certain number, and then I create a group instance for those users (in a separate Entity Group). </p>