self-hosting/roles/nextcloud-docker/templates/nextcloud/config/database.config.php

<?php
$CONFIG = array (
  'dbtype' => 'pgsql',
  'dbname' => 'nextcloud',
  'dbhost' => 'postgres',
  'dbtableprefix' => 'oc_',
  'dbuser' => 'nextcloud',
  'dbpassword' => '{{nextcloud_mysql_password}}'
);