Create documentation to support the Oncology Extension Proposal.

[mgurley]

This documentation will be the basis for a public facing website and content for tutorials.

• Describe overall description and mission of the project.
• Describe major entities and concepts.
• Instructions for implementing the oncology extension.
• Include use cases on public facing website.

[sratwani]

It was decided in the meeting on 10/17 that this task will be completed after other development of NAACCR.