title: How to migrate model with ClassicWithBackgroundCoordinatorSQLiteMagicalRecordStack on MagicalRecord 3.0?
body: <p>I'm using MagicalRecord 3.0's <code>ClassicWithBackgroundCoordinatorSQLiteMagicalRecordStack</code> stack, which allows for the creation of two persistent store coordinators and a single physical store. It works well and I'm quite happy with it.</p>
  
  <p>I now need to migrate my data model. I versioned my model, but the migration is not triggered and the app crashes (unless I delete the app and reinstall fresh).</p>
  
  <p>The change is minor and should be a lightweight migration. How can I trigger an appropriate migration in this situation? Thanks.</p>