At project or group level : Settings >> CI/CD >> Variables
DOCKERHUB_USER
DOCKERHUB_PASSWORD
https://gitlab.com/gitlab-org/gitlab-ce/tree/master/lib/gitlab/ci/templates
At project or group level : Settings >> CI/CD >> Variables
DOCKERHUB_USER
DOCKERHUB_PASSWORD
https://gitlab.com/gitlab-org/gitlab-ce/tree/master/lib/gitlab/ci/templates