add ER diagram

Author: MCSwainConnor

README.md

@@ -15,3 +15,44 @@ npm run prisma generate
 npm run prisma:reset    # reset and reseed the db for dev before starting the dev server
 npm run start:dev
 ```
+
+# Entity Relation Diagram
+
+To see the diagram download the extension bierner.markdown-mermaid in vscode
+
+```mermaid
+erDiagram
+    direction RL
+    User ||--o{ ORDER : creates
+    ORDER ||--}| ORDER_ITEM : contains
+    PRODUCT ||--o{ ORDER_ITEM  : reference
+    User {
+        string id PK "UUID"
+        string name
+        string email UK
+        string password "hash"
+        string createdAt "Timestamp w Zone"
+    }
+    ORDER {
+        string id PK "UUID"
+        string idUser FK
+        date createdAt  "Timestamp w Zone"
+        string status  "Created, Ordered, Canceled, Done"
+    }
+    PRODUCT {
+        string id PK "UUID"
+        string name
+        string size "nullable"
+        string description "nullable"
+        date   createdAt "Timestamp w Zone"
+    }
+    ORDER_ITEM {
+        string id PK "UUID"
+        string idProduct FK "UUID from PRODUCT"
+        string idOrder FK "UUID from ORDER"
+        string name  "name from PRODUCT"
+        string size  "size from PRODUCT | nullable"
+        string description "description from PRODUCT | nullable"
+        int quantity
+    }
+```