With Gogs' ability to authenticate over SMTP it is trivial to integrate it with mailcow. Few changes are needed:

1\. Open `docker-compose.override.yml` and add Gogs:

```
version: '2.1'
services:

    gogs-mailcow:
      image: gogs/gogs
      volumes:
        - ./data/gogs:/data
      networks:
        mailcow-network:
          aliases:
            - gogs
      ports:
        - "${GOGS_SSH_PORT:-127.0.0.1:4000}:22"
```

2\. Create `data/conf/nginx/site.gogs.custom`, add:
```
location /gogs/ {
    proxy_pass http://gogs:3000/;
}
```

3\. Open `mailcow.conf` and define the binding you want Gogs to use for SSH. Example:

```
GOGS_SSH_PORT=127.0.0.1:4000
```

5\. Run `docker-compose up -d` to bring up the Gogs container and run `docker-compose restart nginx-mailcow` afterwards.

6\. Open `http://${MAILCOW_HOSTNAME}/gogs/`, for example `http://mx.example.org/gogs/`. For database details set `mysql` as database host. Use the value of DBNAME found in mailcow.conf as database name, DBUSER as database user and DBPASS as database password.

7\. Once the installation is complete, login as admin and set "settings" -> "authorization" -> "enable SMTP". SMTP Host should be `postfix` with port `587`, set `Skip TLS Verify` as we are using an unlisted SAN ("postfix" is most likely not part of your certificate).

8\. Create `data/gogs/gogs/conf/app.ini` and set following values. You can consult [Gogs cheat sheet](https://gogs.io/docs/advanced/configuration_cheat_sheet) for their meaning and other possible values.

```
[server]
SSH_LISTEN_PORT = 22
# For GOGS_SSH_PORT=127.0.0.1:4000 in mailcow.conf, set:
SSH_DOMAIN = 127.0.0.1
SSH_PORT = 4000
# For MAILCOW_HOSTNAME=mx.example.org in mailcow.conf (and default ports for HTTPS), set:
ROOT_URL = https://mx.example.org/gogs/
```

9\. Restart Gogs with `docker-compose restart gogs-mailcow`. Your users should be able to login with mailcow managed accounts.