All you need to do in your repo, is
Go to Settings > Webhooks & services, "Add webhook"
https://github.com/open-austin/[your-repo-name]/settings/hooks/new
Copy paste the "Payload url" from another repo like: https://github.com/open-austin/project-ideas/settings/hooks
Or ask the open austin core team for help (info [at] open-austin.org)