Add ER diagram to README

Author: peteryates

README.md

@@ -1,55 +1,13 @@
-# README
-
-This README would normally document whatever steps are necessary to get the
-application up and running.
-
-Things you may want to cover:
-
-* Ruby version
-
-* System dependencies
-
-* Configuration
-
-* Database creation
-
-* Database initialization
-
-* How to run the test suite
-
-* Services (job queues, cache servers, search engines, etc.)
-
-* Deployment instructions
-
-* ...
-
-## Setup
-
-### Prerequisites
-
-This project depends on:
-
-  - [Ruby](https://www.ruby-lang.org/)
-  - [Ruby on Rails](https://rubyonrails.org/)
-  - [NodeJS](https://nodejs.org/)
-  - [Yarn](https://yarnpkg.com/)
-  - [Postgres](https://www.postgresql.org/)
-
-### Intellisense
-
-[solargraph](https://github.com/castwide/solargraph) is bundled as part of the
-development dependencies. You need to [set it up for your
-editor](https://github.com/castwide/solargraph#using-solargraph), and then run
-this command to index your local bundle (re-run if/when we install new
-dependencies and you want completion):
-
-```sh
-bin/bundle exec yard gems
-```
-
-You'll also need to configure your editor's `solargraph` plugin to
-`useBundler`:
-
-```diff
-+  "solargraph.useBundler": true,
+```mermaid
+erDiagram
+    Teacher ||--o{ EmailAddress : ""
+    Teacher ||--o{ Mentorship : "Mentor"
+    Teacher ||--o{ Tenureship : ""
+    School ||--|{ Tenureship : ""
+    Tenureship ||--|{ Mentorship : "Mentee"
+
+    School ||--|{ School : "Trust"
+    Mentorship ||--|{ InductionPeriod : ""
+    AppropriateBody ||--|{ InductionPeriod : ""
+    InductionProgramme ||--|{ InductionPeriod : ""
 ```