title: Does searchkick automatically update the index after model has been created?
body: <p>When I include searchkick in an AR model like so:</p>
  
  <pre><code>class Dog &lt; ActiveRecord::Base
    searchkick # callbacks: :async
  end
  </code></pre>
  
  <p>Is the index synced automatically when I create a new Dog model, or do I have to implement this is an <code>after_commit</code> callback? I found the docs to be somewhat ambiguous on that point and I have not been able to verify this behavior in my tests.</p>