Local GitLab hostname

I have the default LAMP stack installed on Ubuntu 16.04 on my laptop.

Today I wanted to try installing GitLab locally to track changes to my development website. I followed the Omnibus installation instructions:

(1) sudo apt-get install curl openssh-server ca-certificates postfix
(2) curl -sS https://packages.gitlab.com/install/repositories/gitlab/gitlab-ce/script.deb.sh | sudo bash
    sudo apt-get install gitlab-ce
(3) sudo gitlab-ctl reconfigure

But I got stuck on 4. Browse to the hostname and login – I just couldn’t understand what hostname to browse to. I tried setting up a different “external URL” by changing this line in gitlab.rb:

external_url "http://gitlab.dev"

and adding this line in /etc/hosts:    gitlab.dev

But opening http://gitlab.dev keeps showing me the root of the webserver (i.e., /var/www/html/index.php in my case) instead of some GitLab page. What should I do to open GitLab locally in the browser?

(Also, at some point http://gitlab.dev even randomly redirected to https://about.gitlab.com for some unknown reason.)