As per [Slack conversation](https://gitlab.slack.com/archives/C3JJET4Q6/p1502860290000046), using multi-project pipelines to better integrate building of gitlab-omnibus is not yet possible. Developers on `gitlab-ce` are not allowed to run a pipeline on `omnibus-gitlab` since we now have #30634 so you need to have push/merge permissions on the target project. They need to do that in order to have a Docker image with the latest changes that they can use to test locally. Now the process is done by a bot user that creates the image, but it should be done with MPP. Not sure if this is the right project for this issue, in case let's move it to `gitlab-ce` or `omnibus-gitlab`.