Add new webhooks and customize webhook payload

Hi, I’m trying to create a custom webhook following this guide and sample plugin, but I can not get my new custom event types to show up in the webhook UI. I tried installing the plugin linked in this guide in my local dev instance and the events in this example plugin do not show up either. I’m guessing something changed between 2017 and now which affects this?

Does anyone here know how to get the example plugin in this topic to work? I suspect the problem might be with the seeding code for the database since the new entries aren’t showing up in the /admin/api/web_hooks response. As it currently stands, this guide is not functional. Thanks!