title: Deploying a sequelize-cli app to heroku DATABASE_URL issue
body: <p>I'm using sequelize migrations. Here is my config.js:</p>
  
  <pre class="lang-js prettyprint-override"><code>require('dotenv').config()
  
  module.exports = {
    development: {
      database: process.env.DEV_DATABASE,
      host: process.env.DEV_HOST,
      dialect: 'postgres'
    },
    test: {
      database: process.env.TEST_DATABASE,
      host: process.env.TEST_HOST,
      dialect: 'postgres'
    },
    production: {
      database: process.env.DATABASE_URL,
      dialect: 'postgres'
    },
  }
  </code></pre>
  
  <p>When I deploy to heroku and run:</p>
  
  <pre class="lang-sh prettyprint-override"><code>heroku run npx sequelize-cli db:migrate
  </code></pre>
  
  <p>I get the error:</p>
  
  <pre class="lang-sh prettyprint-override"><code>Loaded configuration file "config/config.js".
  Using environment "production".
  
  ERROR: connect ECONNREFUSED 127.0.0.1:5432
  </code></pre>
  
  <p>I have tried changing my config to <code>use_env_variable: DATABASE_URL</code> and I get <code>Error reading "config/config.js". Error: ReferenceError: DATABASE_URL is not defined</code></p>
  
  <p>If I <code>console.log(process.env.DATABASE_URL)</code> I get something like:</p>
  
  <pre><code>postgres://bczwqcbnwftivi:80bbc89546c0953e0ffd221a950cac249d25d4ef1812127054af7c2f504b2c39@ec2-54-225-205-79.compute-1.amazonaws.com:5432/d8gsvl0n8qilcs
  </code></pre>