title: How to use build for adding to ActiveRecord collection
body: <p>I have a model called PhoneItems which has many CallingTimes.
  To disable the has_many autosave functionality I had to start using the build method.</p>
  
  <pre><code>phone_queue_items.calling_times.build
  </code></pre>
  
  <p>so that when the edit form is closed, the calling time isn't automatically saved. Now I have the following problem. I want to be able to push a second calling_time to the PhoneItem object, however the following is not working:</p>
  
  <pre><code>phone_queue_items.calling_times &lt;&lt; CallingTimes.build
  </code></pre>
  
  <p>nor
      phone_queue_items.calling_times.build</p>
  
  <p>Is there any way to do build more than one calling time in the phone_queue_item object?</p>