title: Sequelize: using build to update a record
body: <p>Let's say I have the following simple model:</p>
  
  <pre><code>var Foo = sequelize.define('Foo', {
      bar: Sequelize.STRING,
  });
  </code></pre>
  
  <p>And the table <code>Foos</code> in the database has a record:</p>
  
  <pre><code>id   bar
  ---  ---
  1    abc
  </code></pre>
  
  <p>In order to update this record I could do the following:</p>
  
  <pre><code>Foo.findById(1).then(function(foo) {
      foo.bar = 'xyz';
      foo.save();
  });
  </code></pre>
  
  <p>Now I have found another way to update the record without having to find it form the database:</p>
  
  <pre><code>var foo = Foo.build({ id: 1, bar: 'xyz' });
  foo.isNewRecord = false;  // makes save use UPDATE instead of INSERT INTO
  foo.save();
  </code></pre>
  
  <p>This is perfect for my use case, but I'm wondering if I'm breaking anything in sequelize.</p>