Integration with message bus (rabbitmq)

Problem to solve

In order to integrate GitLab with other services it would be great if there was a way to publish GitLab events on a message bus for example rabbitmq. That would allow to have consumers reacting on these events.

Intended users

This is useful for integrating GitLab in existing infrastructure which are already making use of a message bus.

User experience goal

It should be possible to configure a GitLab instance to publish events on a message bus (rabbitmq prefered). If the instance is configured all the events happening on that instance would be published on the bus.