title: What methods/mixins sequelize adds to the models when an association is made?
body: <p>While going through the <a href="http://docs.sequelizejs.com" rel="noreferrer">sequelize docs</a>, more specifically the <a href="http://docs.sequelizejs.com/manual/tutorial/associations.html" rel="noreferrer">documentations about associations</a>, I see that the guide casually shows the reader methods such as <code>setTasks()</code>, <code>addTask()</code>, <code>setProject()</code>, that seem to be automatically created by sequelize for all model instances with respect to the created associations.</p>
  
  <p>I couldn't find detailed information on what methods are available, and whether they are created with the singular version or plural version (since there is both <code>setTasks()</code> and <code>setProject()</code>, for example), and what exactly are the parameters they expect, and such. <a href="http://docs.sequelizejs.com/manual/tutorial/associations.html" rel="noreferrer">The docs</a> apparently just casually mention them inside the examples...</p>
  
  <p><strong>So, what methods/mixins sequelize adds to the models when an association is made?</strong> And what are the parameters and return values, i.e. what's the documentation for those methods? Or, at least, where can I find them?</p>