title: Sequelize Postgres - How to use ON CONFLICT for unique?
body: <p>I am implementing <code>sequelize</code> into my NodeJS application. Before this, I was using a written INSERT query that used <code>ON CONFLICT (field) DO NOTHING</code> to handle not inserting records where a value needed to be unique.</p>
  
  <pre><code>const sql = 'INSERT INTO communications (firstname, lastname, age, department, campus, state, message_uuid) VALUES ($1, $2, $3, $4, $5, $6, $7) ON CONFLICT (message_uuid) DO NOTHING';
  
  const values = [val.firstName, val.lastName, val.age, val.department, val.campus, val.state, message_uuid];
  </code></pre>
  
  <p>Is there support for this in sequelize where I can define the same thing within a model? Or perhaps a better way to handle it?</p>
  
  <p>Essentially, if a record already exists in the table in the column with <code>message_uuid</code> = 123 and another record try's to insert that has that same value, it ignores it and does nothing.</p>