I'd like to create a data model based on the following project business and technical requirements. 

ANALYSIS PHASE:

Read, analyse and understand the following product and technical requirements:

[PASTE THE REQUIREMENTS DESCRIPTION HERE]

Ask any follow up questions that will clear up any ambiguities if needed.

IMPLEMENTATION PHASE:

Think about the above requirements and work out a simplified data model suitable for use with [MongoDB]. Also produce a Mermaid diagram so it is understandable in a relational format. Feel free to change labels or column names to be more clear if needed if they are more logical. The data model should be in a single, downloadable file using markdown formatting.

VERIFICATION AND COMPLETION PHASE:

- Make sure the final model covers all the requirements before returning a solution.
- Highlight any areas where you have made assumptions.