title: Documentation for node.js sequelize index lookup
body: <p>I'm having trouble finding information about how to look up records by an index using sequelize/postgres for node.js.</p>
  
  <p>The only documentation of indexes appears to be here: <a href="http://sequelizejs.com/documentation#migrations-functions" rel="nofollow">http://sequelizejs.com/documentation#migrations-functions</a></p>
  
  <p>To illustrate what I'm asking, let's take a simple model where there is a person there are Persons, Projects, and Tasks. Each person references a number of assigned tasks, and each project has a number of assigned tasks. Each task has a back-reference to the project and person. We'll assume that each person only has one task per project. </p>
  
  <p>Let's say I have a person and project, and I need to find if there is a task associated. I've tried implementing this through an index on task of person/project. </p>
  
  <p>I've found through searches that you can also create indexes through the slightly unintuitive syntax:</p>
  
  <pre><code>        global.db.sequelize.getQueryInterface().addIndex('Tasks',
          ['ProjectId', 'PersonId'],
          {
              indexName: 'IndexName',
              indicesType: 'UNIQUE'
          }
  </code></pre>
  
  <p>This seems to work, and the index is created. However, I can't find a reference anywhere in the docs or even on the internet about how to use this index to find the task. </p>
  
  <p>Any suggestions?</p>