nodebb_ynh/conf/config.json

{
    "url": "http://__URL__:__PORT__",
    "secret": "__SECRET__",
    "database": "mongo",
    "mongo": {
        "host": "127.0.0.1",
        "port": "27017",
        "username": "dbuser",
        "password": "dbpass",
        "database": "dbname"
    }
}