Verify you can associate multiple payments after updating the data model

UpdateRelationshipDemo.java

final Invoice myLatestInvoice = (Invoice)persistenceManager.findById(Invoice.class, 1l);

// This used to be a single entity and now it is a list of payments since the relationship has changed from a One To One
// to a One To Many.  This is also handled by the light weight migration.
List<Payment> paymentList = myLatestInvoice.getPayments();

// What previously was a one to one relationship should have the existing record in the set.
assert paymentList.size() == 1;
assert paymentList.get(0).getPaymentId() == 1;

// Lets add another payment to ensure we can have a ToMany Relationship
final Payment mySecondPayment = new Payment();
mySecondPayment.setAmount(10.01);
mySecondPayment.setNotes("Getting a start on next months bill since I don't have enough money because I am too busy writing open source software and not focusing on my day job.");
mySecondPayment.setInvoice(myLatestInvoice);

// Persist the Payment
persistenceManager.saveEntity(mySecondPayment);

// Refresh the collection and ensure there are 2 items
persistenceManager.initialize(myLatestInvoice, "payments");

assert paymentList.size() == 2;