Update README.md

README.md

@@ -8,6 +8,14 @@ graph TD;
 ```    
 
 ```mermaid
+erDiagram;
+    t_client_user  ||--o{ t_client_user_device : has;
+    t_client_user_device }|--|| t_user_device_group : related;
+
+```
+
+
+```mermaid
 erDiagram
     t_client_user  ||--o{ t_client_user_device : has
     t_client_user_device }|--|| t_user_device_group : related