Gitlab + nexus docker registry

I have gitlab-ce(gitlab/gitlab-ce:latest) in docker container and docker registry in container(sonatype/nexus3) on different hosts
I can’t configure docker registry in gitlab.
Can anyone help me?

P.S. I cant understand what i have to do. Configuration options require certificates, but i have not any certificates. I think it works over http. With basic authorization.
docker login - docker pull works fine. What i have to do to connect this registry to my gitlab instance.

P.P.S Sorry for my English. I’m not english speaking