Publish grads open for work on People channel

## I want to do this:

Develop the graduate entry type on the People channel on the new CYF website https://github.com/CodeYourFuture/cyf-main-website

## Here’s why I want to do it:
- Trainees have built a graduate directory or register a bunch of times, but it always gets lost. An entry type on our website would be more discoverable
- It would be useful for the Employment Programme to have a portfolio of grads they can share with prospective employers
- It would be useful for grads to be represented on our website, which should also be their website
- It would be a good, chunky, impactful piece of UI to build for someone's portfolio

## Here’s how it serves our goals:
- Our trainees represent us, we should represent our trainees

## This is how much time I can put towards this change:
- I can pair with a grad to build this, for up to 6 121 sessions in total

## This is the help I need from others to get this done (if any):
- I need someone to deploy the new website #3

まず、Issue にリンクされている新しい CYF ウェブサイトを確認し、People チャンネルと、graduate のエントリータイプがどのように表示されるべきかに注目してください。作業を計画する前に、deployment issue #3 を確認してください。graduate directory のエントリータイプが実装され、People チャンネルで公開されれば完了です。

索引モデルが issue の本文から書いたものです。