Set up Docker Swarm and [abra][abra]
Deploy [coop-cloud/traefik][cc-traefik]
abra app new gitea --secrets (optionally with --pass if you'd like to save secrets in pass)
abra app config YOURAPPDOMAIN - be sure to change $DOMAIN to something that resolves to your Docker swarm box
abra app deploy YOURAPPDOMAIN

Create first user

Run

abra app run YOURAPPNAME app gitea -c /etc/gitea/app.ini admin user create --username USERNAME --admin --random-password --email EMAIL

See the Gitea command-line documentation for more options. Make sure not to forget the -c /etc/gitea/app.ini.

Enable SSH

You most certainly want to be able to access your repository over SSH. To do so, make sure you uncomment the right lines in the configuration for traefik.

abra app config YOURTRAEFIKAPP

There uncomment or add these lines:

GITEA_SSH_ENABLED=1
COMPOSE_FILE="compose.yml:compose.gitea.yml"

Then redeploy traefik:

abra app undeploy YOURTRAEFIKAPP
abra app deploy YOURTRAEFIKAPP

You might need to wait a bit. To check if it worked, you can run

telnet my.gitea.example.com 2222

Once you have added a public SSH key, you can check that you can connect to your gitea server with

ssh -T -p 2222 git@my.gitea.example.com

Note that gitea should be configured to listen to port 2222, i.e. GITEA_SSH_PORT=2222 in the gitea config.