title: Using Meteor to do $push and $set at the same time
body: <p>Is it possible to use Meteor to do both a <code>$push</code> and a <code>$set</code> in the same operation? </p>
  
  <p>I want it to be in the same operation so a <code>cursor.observe</code> will not be triggered twice by splitting up into 2 different MongoDB operations.</p>
  
  <p>Currently, the following fails to insert into the array:</p>
  
  <pre><code>Animals.update(
      {_id: animal_id}, 
      { 
          $set: {
              driver_id: '', 
              status: 'feeding'
          }, 
          $push: {
              feeder: Meteor.user()._id 
          }
      }   
  )
  </code></pre>
  
  <p>For <code>$push</code> to work, it needs to be split into 2:</p>
  
  <pre><code>Animals.update(
      {_id: animal_id}, 
      { $set: 
          {
              driver_id: '', 
              status: 'feeding'
          }
      }
  Animals.update(
      {_id: animal_id}, 
      {
          $push: {
              feeder: Meteor.user()._id 
          }
      }   
  </code></pre>