update

pkg/checkout/checkout-grain.go

@@ -75,9 +75,10 @@ func (p *Payment) IsSettled() bool {
 }
 
 type ContactDetails struct {
-	Email *string `json:"email,omitempty"`
-	Phone *string `json:"phone,omitempty"`
-	Name  *string `json:"name,omitempty"`
+	Email      *string `json:"email,omitempty"`
+	Phone      *string `json:"phone,omitempty"`
+	Name       *string `json:"name,omitempty"`
+	PostalCode *string `json:"zip,omitempty"`
 }
 
 type ConfirmationStatus struct {

pkg/checkout/mutation_contact_details_updated.go

@@ -16,6 +16,10 @@ func HandleContactDetailsUpdated(g *CheckoutGrain, m *checkout_messages.ContactD
 		g.ContactDetails = &ContactDetails{}
 	}
 
+	if m.PostalCode != nil {
+		g.ContactDetails.PostalCode = m.PostalCode
+	}
+
 	if m.Email != nil {
 		g.ContactDetails.Email = m.Email
 	}