Organize backend into product executable and shared Go modules

backend/shared/logging/fields/error.go

@@ -0,0 +1,14 @@
+package mzap
+
+import (
+	"reflect"
+
+	"go.uber.org/zap"
+)
+
+func ErrorType(err error) zap.Field {
+	if err == nil {
+		return zap.String("error_type", "")
+	}
+	return zap.String("error_type", reflect.TypeOf(err).String())
+}