More tweaks for CORE <-> Rattail member sync

rattail_corepos/db/model/people.py

@@ -132,6 +132,9 @@ class CoreCustomerShopper(model.Base):
             cascade='all, delete-orphan',
             cascade_backrefs=False))
 
+    # please note, there is *not* a unique constraint on this field.
+    # that is intentional, for now, to give some breathing room for
+    # testing etc.
     corepos_customer_id = sa.Column(sa.Integer(), nullable=True, doc="""
     ``Customers.customerID`` value for this shopper, within CORE-POS.
     """)