title: How to create a new Sequelize dialect, for example DB2
body: <p><a href="https://github.com/sequelize/sequelize">Sequelize</a> supports five flavours of DBMS. In my project, we have a legacy database located in an IBM DB2, which is not in that list. There exists a <a href="https://www.npmjs.com/package/ibm_db">node driver for DB2</a>, published by IBM.</p>
  
  <ol>
  <li>Is there a documentation on how to create such a new dialect for Sequelize? </li>
  <li>Is it encouraged?</li>
  </ol>