GitLab install snafu

gistfile1.txt

I'm trying to install and run the Omnibus GitLab container on a 2008 Mac Pro
running OSX 10.10.5.  I installed the Docker Toolbox and kicked the tires:

$ docker --version
$ docker-compose --version
$ docker-machine --version
$ docker ps
$ docker run hello-world
$ docker run -d -p 80:80 --name webserver nginx
# Browse to http://192.168.99.100 to see "Welcome to nginx!".

I then ran this command to install the GitLab Docker image:

$ sudo docker run --detach \
    --hostname gitlab.example.com \
    --publish 443:443 --publish 80:80 --publish 22:22 \
    --name gitlab \
    --restart always \
    --volume /srv/gitlab/config:/etc/gitlab \
    --volume /srv/gitlab/logs:/var/log/gitlab \
    --volume /srv/gitlab/data:/var/opt/gitlab \
    gitlab/gitlab-ce:latest
    
    Sadly, this complains:

docker: Cannot connect to the Docker daemon at unix:///var/run/docker.sock.
  Is the docker daemon running?.  See 'docker run --help'.