When you uninstall GitLab and then reinstall it, running `sudo gitlab-ctl reconfigure` often gets stuck at: `ruby_block[supervise_redis_sleep] action run` and cannot proceed!
Solution:
1. Press CTRL+C to force quit;
2. Run: `sudo systemctl restart gitlab-runsvdir`;
3. Run again: `sudo gitlab-ctl reconfigure`
Solution source: https://gitlab.com/gitlab-org/omnibus-gitlab/issues/160