Create UML Class Diagram

## Description

We need to create a UML class diagram model for our application. Which shows the different classes and their main methods and attributes.

## Requirements

When this is complete, we must copy the image version of the diagram to our wiki.

## Links
[UML class diagram GenMyModel](https://app.genmymodel.com/editor/edit/__CHH8FpxEe2ck8ytUMEi6A#)