Remove default empty classes.
Add Customer class.
Add test using Customer.
Update the project file.
Add a dummy Order class to make the test compile.
Fix other project file.
Add Builder for Customer.
Move Order class to another file.
Add a builder for Orders.
Define Equality on Customer and a Resemblance.

The production Equality for Customers should be by ID, but for some tests
we might be interested in name instead.