title: Is there a guarantee that ActiveRecord returns objects ordered by ID?
body: <p>My project is hosted on Heroku.
  I was surprised when <code>Room.all</code> method returned objects with <code>first object with ID 2</code> and only then a <code>second object with ID 1</code>. I thought that there were some sort of guarantee that objects are returned already ordered by ID. Should I always call <code>Room.all.order(:id)</code> instead of regular <code>all</code> method?</p>
  
  <pre><code>irb(main):002:0&gt; Room.all
  =&gt; #&lt;ActiveRecord::Relation [
      #&lt;Room id: 2, color: "rgb(83, 180, 83)", status: "Status #2", created_at: "2014-10-11 14:14:02", updated_at: "2014-10-11 14:18:19"&gt;, 
      #&lt;Room id: 1, color: "rgb(0, 96, 255)", status: "Status #3", created_at: "2014-10-11 14:14:02", updated_at: "2014-10-11 14:18:30"&gt;
    ]&gt;
  </code></pre>