title: Rails render partial with :collection
body: <p>This is so simple it shouldnt be an issue but I dont understand whats going on here. </p>
  
  <p>I have the following code </p>
  
  <pre><code>class DashboardController &lt; ApplicationController
      def bookings
        @bookings = Booking.all
      end
  end
  </code></pre>
  
  <p>/views/dashboard/bookings.html.erb</p>
  
  <pre><code>&lt;%= render 'booking', :collection =&gt; @bookings %&gt;
  </code></pre>
  
  <p>/views/dashboard/_booking.html.erb</p>
  
  <pre><code>&lt;%= booking.booking_time %&gt;
  </code></pre>
  
  <p>I get the following error</p>
  
  <pre><code>undefined method `booking_time' for nil:NilClass
  </code></pre>
  
  <p>However if I do this in /views/dashboard/_bookings.html.erb</p>
  
  <pre><code>&lt;% @bookings.each do |booking| %&gt;
     &lt;%= render 'booking', :booking =&gt; booking %&gt;
  &lt;% end %&gt;
  </code></pre>
  
  <p>I get (correct)</p>
  
  <pre><code>2012-12-19 09:00:00 UTC 
  2012-12-28 03:00:00 UTC
  </code></pre>
  
  <p>Whats going on here? I really want to use :collection as defined here 
  <a href="http://guides.rubyonrails.org/layouts_and_rendering.html" rel="noreferrer">http://guides.rubyonrails.org/layouts_and_rendering.html</a></p>