title: Ordering of has_and_belongs_to_many associations
body: <p>In my rails app I have two models that are related by has_and_belongs_to_many.  This means there is a join table.</p>
  
  <p>Imagine the scenario where I am adding users to a game. If I want to add a user, I do:</p>
  
  <pre><code>@game.users &lt;&lt; @user
  </code></pre>
  
  <p>Supposing that I want to know in what order I added these users.  I can do this:</p>
  
  <pre><code>@game.users.each do....
  </code></pre>
  
  <p>My questions are:</p>
  
  <ol>
  <li><p>Is the ordering if this list guaranteed to read the same way each time?</p></li>
  <li><p>If that's the case, What's a clean way to reorder the users in the game?</p></li>
  </ol>