title: Adding scope to ActiveRecord causes hierarchy error
body: <p>I've just converted all of my Rails models to use <code>uuid</code> as a primary key replacement, but this breaks the <code>#first</code> and <code>#last</code> methods so I'm trying to add a default scope that sorts by <code>created_at</code> instead of <code>id</code>.</p>
  
  <p>My concern looks like this:</p>
  
  <pre><code># config/initializers/uuid_support.rb
  module 
    extend ActiveSupport::Concern
  
    included do
      default_scope -&gt; { order 'created_at ASC' }
    end
  end
  ActiveRecord::Base.send :include, UuidSupport
  </code></pre>
  
  <p>Once this has been added, the following error gets thrown when performing a fetch on any model: <code>ActiveRecord::ActiveRecordError: ActiveRecord::Base doesn't belong in a hierarchy descending from ActiveRecord</code>.</p>