moved uml.md to docs/archive/

docs/archive/uml.md

@@ -0,0 +1,27 @@
+# UML Model
+
+## Class Diagram
+
+<!---
+```plantuml
+@startuml
+class User {
+    - id: int
+    - name: string
+    - email: string
+    - password: string
+    + getId(): int
+    + getName(): string
+    + getEmail(): string
+    + getPassword(): string
+    + setId(id: int): void
+    + setName(name: string): void
+    + setEmail(email: string): void
+    + setPassword(password: string): void
+}
+@enduml
+```
+-->
+
+Archived. Please see new UML diagram uploaded in chats. Thanks!
+