Updating GitLab configuration

This gitlab instance is using the omnibus package. See GitLab Omnibus Reconfigure for official docs on reconfiguration. Here are the basic steps:

Update the GITLAB_OMNIBUS_CONFIG environment variable in docker-compose.yml. Add the desired omnibus configuration lines.
Run docker exec -it gitlab /bin/bash to enter the container.
Run vi /etc/gitlab/gitlab.rb to begin editing the config file. Make the necessary changes (i to enter insert mode), then save (esc, then :wq, enter).
Run gitlab-ctl diff-config to compare the new config file with the default config file (not previous).
Run gitlab-ctl reconfigure to apply the changes.
Confirm the value set in step 1 is still correct.