Add memory store
diff --git a/core/kg/model/user.go b/core/kg/model/user.go
index 6feb948..156f4fa 100644
--- a/core/kg/model/user.go
+++ b/core/kg/model/user.go
@@ -46,6 +46,11 @@
 	return nil
 }
 
+func (u *User) Clone() *User {
+	user := *u
+	return &user
+}
+
 func isValidID(value string) bool {
 	if len(value) != 26 {
 		return false