dbConfig.js

const knex = require('knex');

const config = require('./knexfile.js');

// if the environment variable is not set, default to 'development'
// this variable is only set when running the "test" npm script using npm run test
const dbEnv = process.env.DB_ENV || 'development';

// the value of dbEnv will be either 'development' or 'testing'
// we pass it within brackets to select the corresponding configuration
// from knexfile.js
module.exports = knex(config[dbEnv]);