How can I connect my local node.js app to my Heroku Postgres database?

I've managed to get my Node.js app working properly with my Heroku Postgres database when the node application is deployed to Heroku. However having to deploy to heroku each time I make a code change is a bit arduous and I'd rather be able to develop locally and connect to the database from my local app.

https://devcenter.heroku.com/articles/connecting-to-heroku-postgres-databases-from-outside-of-heroku

The above article doesn't really describe how this is done, I'm not exactly sure what I need to do.

If I attempt to run my app locally and access an endpoint that queries my database I get

Error Error: connect ECONNREFUSED 127.0.0.1:5432

Whereas if I access the same endpoint from my heroku deployed app it works correctly.

Here's my app

const express = require('express')
const path = require('path')
const PORT = process.env.PORT || 5000;
const { Pool } = require('pg');

const pool = new Pool({
    connectionString: process.env.DATABASE_URL,
    ssl: {
        rejectUnauthorized: false
    }
});

express()
  .use(express.static(path.join(__dirname, 'public')))
  .set('views', path.join(__dirname, 'views'))
  .set('view engine', 'ejs')
  .get('/', (req, res) => res.render('pages/index'))
    .get('/users', async (req, res) => {
        try {
            const client = await pool.connect();
            const result = await client.query('SELECT * FROM users');
            const results = { 'results': (result) ? result.rows : null};
            console.log(results);
            res.status(200).json(results);
        } catch (err) {
            console.error(err);
            res.send("Error " + err);
        }
    })
  .listen(PORT, () => console.log(`Listening on ${ PORT }`));