for postgresql the pg_config.js file should sit on the root and look like the example below
(function(pg_config){
pg_config.host = "eample.com";
pg_config.port = 5432;
pg_config.dbname = "dbName";
pg_config.user = "dbUser";
pg_config.sslmode = "require";
pg_config.password = "password";
}(typeof module == 'object' ? module.exports : {}))