Webhook for stuff happening on groups

Description

We're building https://gitlab.com/gitmate/open-source/IGitt and gitmate.io and are lacking a group level webhook to stay up to date to the number of users of the GitLab instance for billing but also for newly created repositories so we don't have to poll for that. (Cause we don't want to be hitting your API so much)

Proposal

There should be group level webhooks

Links / references

• https://gitlab.com/gitmate/open-source/IGitt/blob/master/IGitt/GitLab/GitLab.py#L109

Documentation blurb

Overview

this helps you grow GitLab as a Platform

Use cases

Every serious integration with GitLab will eventually want and need this

Feature checklist

• Webhook notifying people when users are added to groups/subgroups
• Webhook notifying for renamed repos
• Webhook notifying for deleted repos
• Webhook notifying for new repos