Gitlab image behind reverse proxy (Traefik)

Dear friends,
I was wondering if it’s possible to run GitLab docker containers behind a reverse proxy using path based routing.
In general, images that support this (Jenkins, Kong, Swarmpit, Gogs, Sonarqube) support specifying via an env variable the base path, ie:

jenkins support 
    environment:
        - JENKINS_OPTS="--prefix=/jenkins"

sonarqube:
  image: bitnami/sonarqube:7.6.0
  environment:
    - SONARQUBE_WEB_CONTEXT=/sonarqube

and so on so forth.
I’ve not found anything of this sort in the documentation of the docker image for GitLab CE.
Can you point me to the right direction?
Thank you,
Roberto