Non-standard port for database

[counterpoint]

Is there a way to access the database using a port other than the default? I tried changing .env with a line:
MAILMAN_HOST=127.0.0.1:4002
but that seemed to break the system, as no login was then possible. Is there a way to do this, or could I request some way to do it? I want to access a remote database via an SSH tunnel.

[counterpoint]

Seems like an additional parameter is essential to make this work. Something along the lines of this from a different application that uses knex:
{
name: 'global',
client: 'pg',
debug: false,
connection: {
multipleStatements: true,
host: url.parse(process.env.DB_PORT).hostname,
user: process.env.DB_USER,
port: parseInt(url.parse(process.env.DB_PORT).port, 10),
password: process.env.DB_PASSWORD,
database: process.env.DB_DATABASE,
},
migrations: {
directory:${__dirname}/../db/migrations,
},
}
Or simply set the port from an additional definition in .env. Simple enough to change the source code, but I'm using the docker package, and don't know enough to rebuild it with the change.