title: recreate NSManagedObject subclasses when the model changes in the model editor
body: <p>I was wondering if there was a way to update the NSMangedObject subclass after you change a property or add a field in the Core Data model editor.  Sometimes I add a field, or realize that I accidentally put integer as the type instead of string, but my NSManagedObject subclass was already created.  So instead of manually going in and adding those fields, I was wondering if there was a way for Xcode to just update the model?  Thanks.</p>