Implement WithTransaction() method eq. to WithOrder() (#164)

Author: alex-schneider

logger.go

@@ -14,6 +14,7 @@ const (
 	ShopField           = "shop"
 	CheckoutField       = "checkout"
 	OrderField          = "order"
+	TransactionField    = "transaction"
 	CheckoutDeviceField = "checkoutDevice"
 	DurationField       = "duration"
 	FlakyField          = "flaky"
@@ -90,6 +91,10 @@ func (logger *Logger) WithOrder(order string) *Entry {
 	return NewEntry(logger).WithField(OrderField, order)
 }
 
+func (logger *Logger) WithTransaction(txn string) *Entry {
+	return NewEntry(logger).WithField(TransactionField, txn)
+}
+
 type Entry struct {
 	*logrus.Entry
 }
@@ -164,6 +169,10 @@ func (entry *Entry) WithOrder(orderID string) *Entry {
 	return entry.WithField(OrderField, orderID)
 }
 
+func (entry *Entry) WithTransaction(txnID string) *Entry {
+	return entry.WithField(TransactionField, txnID)
+}
+
 // Deprecation marks the log entry with type "deprecation". This is used for log entries, that are logged during a
 // feature change. Logs with "deprecation" types should not be considered as critical and should only occur temporarily
 // during the transition.