title: How to use array_agg() in sequelize?
body: <p>I want to use array_agg() function with sequelize. How can I do that ?
  I have been used below code, but it doesn't work.</p>
  <pre><code>let statusTabs = await Parameters.findAll({
      where: {
          param_key: 't_status',
          param_name: ['Washing', 'Awaiting', 'Pending']
      },
      attributes: [
          sequelize.literal('array_agg(param_key)'),
          sequelize.fn('array_agg', sequelize.col('param_key'))
      ]
  });
  </code></pre>
  <p>It is giving errors like below -</p>
  <p><strong>TypeError: Cannot read property 'fn' of undefined</strong></p>
  <p><strong>TypeError: Cannot read property 'literal' of undefined</strong></p>
  <p>How can I get array_agg() to work ?</p>