fix: redis pubsub not being required correctly

split connection logic into separate module

src/database/postgres/connection.js

@@ -0,0 +1,45 @@
+'use strict';
+
+const nconf = require('nconf');
+const winston = require('winston');
+const _ = require('lodash');
+
+const connection = module.exports;
+
+connection.getConnectionOptions = function (postgres) {
+	postgres = postgres || nconf.get('postgres');
+	// Sensible defaults for PostgreSQL, if not set
+	if (!postgres.host) {
+		postgres.host = '127.0.0.1';
+	}
+	if (!postgres.port) {
+		postgres.port = 5432;
+	}
+	const dbName = postgres.database;
+	if (dbName === undefined || dbName === '') {
+		winston.warn('You have no database name, using "nodebb"');
+		postgres.database = 'nodebb';
+	}
+
+	var connOptions = {
+		host: postgres.host,
+		port: postgres.port,
+		user: postgres.username,
+		password: postgres.password,
+		database: postgres.database,
+	};
+
+	return _.merge(connOptions, postgres.options || {});
+};
+
+connection.connect = function (options, callback) {
+	const Pool = require('pg').Pool;
+
+	const connOptions = connection.getConnectionOptions(options);
+
+	const db = new Pool(connOptions);
+
+	db.connect(function (err) {
+		callback(err, db);
+	});
+};

src/database/postgres/pubsub.js

@@ -1,15 +1,15 @@
 'use strict';
 
-var util = require('util');
-var winston = require('winston');
-var EventEmitter = require('events').EventEmitter;
-var pg = require('pg');
-var db = require('../postgres');
+const util = require('util');
+const winston = require('winston');
+const EventEmitter = require('events').EventEmitter;
+const pg = require('pg');
+const connection = require('./connection');
 
-var PubSub = function () {
-	var self = this;
+const PubSub = function () {
+	const self = this;
 
-	var subClient = new pg.Client(db.getConnectionOptions());
+	const subClient = new pg.Client(connection.getConnectionOptions());
 
 	subClient.connect(function (err) {
 		if (err) {
@@ -41,6 +41,7 @@ var PubSub = function () {
 util.inherits(PubSub, EventEmitter);
 
 PubSub.prototype.publish = function (event, data) {
+	const db = require('../postgres');
 	db.pool.query({
 		name: 'pubSubPublish',
 		text: `SELECT pg_notify('pubsub', $1::TEXT)`,