Document deploying behind Coolify

[Loa212]

What changed

• add ### Coolify under Install, between Docker and Binaries
• correct the comment on expose added in Declare the port a reverse proxy should send traffic to #13

Why

Coolify derives the Traefik backend port by parsing it out of the domain string, in bootstrap/helpers/docker.php:

$port = $url->getPort();                    // from the DOMAIN, not from the compose file
if (is_null($port) && ! is_null($onlyPort)) {
    $port = $onlyPort;
}
...
if ($port) {                                // no port found ⇒ no backend label at all
    $labels->push("traefik.http.services.{$https_label}.loadbalancer.server.port=$port");
}

With a domain of https://nudo.example.com and no port, the generated labels contain routers matching the hostname and no loadbalancer.server.port. Traefik matches the request, has no backend, and answers 502 — in front of a container that started cleanly and passed its healthcheck, which is what makes this hard to place from the symptom.

Worth stating explicitly in the docs because the obvious candidates all look right and none of them work: expose, a published ports mapping, and the Connect To Predefined Network toggle. None is an input to the code above.

The section also covers NUDO_BASE_URL, which is a second, quieter failure: auth.rs:152 derives the session cookie's Secure flag from the scheme alone, so left at the http://localhost:3000 default behind HTTPS the login page renders and the session silently fails to persist. It is also the base for webhook callback URLs (webhook.rs:347).

On the expose comment

#13 added expose with a comment claiming Coolify reads it to learn the port. The source above shows it does not. The key is kept — stating the dashboard's port in the file a reader is looking at earns its line — but the stated reason was wrong and would send the next person down the same path.

Validation

• NUDO_SECRET_KEY=validation-only docker compose config --quiet
• re-verified both NUDO_BASE_URL claims against crates/web/src/auth.rs, crates/web/src/routes/auth.rs, crates/web/src/webhook.rs
• git diff --check; heading order confirmed (### Docker → ### Coolify → ### Binaries)