[x] Decide where to write / host documentation. Look into GitHub options.We will use the GitHub wiki.
[x] Write a placeholder document / entryway and add a link to the readme.Home page is already there. Link not needed because it's directly attached to the repo.
[x] Survey the codebase and decide which bits are the most confusinig / wuld most benefit from explanation. Write a list of these bits and prioritise in order of confusingness.Written my personal most important things as a list on the home page.
[x] Write tickets to write those docs.Overkill. I'll just do them under this ticket, or without tickets attached. More lightweight that way
[x] Invite other members of the team to add their own contribution. For instance, @dhinrichs-scottlogic might want to add a doc about our approach to accessibility, @chriswilty might want to include something about deployment.
AC: no code changes, therefore no testing needed