see below:
xxx@deb:~/tmp$ curl -sS https://packages.gitlab.com/install/repositories/gitlab/gitlab-ce/script.deb.sh | sudo bash
Detected operating system as debian/jessie.
Checking for curl…
Detected curl…
Running apt-get update… done.
Installing debian-archive-keyring which is needed for installing
apt-transport-https on many Debian systems.
Installing apt-transport-https… done.
Installing /etc/apt/sources.list.d/gitlab_gitlab-ce.list…done.
Importing packagecloud gpg key… done.
Running apt-get update… done.
The repository is setup! You can now install packages.
xxx@deb:~/tmp$ sudo apt-get install gitlab-ce
Reading package lists… Done
Building dependency tree
Reading state information… Done
E: Unable to locate package gitlab-ce