I started sketching out content for a project structure section, but
this quickly branched out to include a variety of topics that are better
described as writing code.

These sections include several exercises. One uses my Australian 2020
COVID-19 forecasts repository as an example and asks the reader to think
about how the README.md file could be improved.

The previous version was far too long and detailed; the intent is to
make a simple point, rather than tell a long story.