title: Model.where(...).first attribute is not nil but shows nil
body: <p>I'm playing with rails console:</p>
  
  <pre><code>a = Event.where("location_id IS NULL")
    Event Load (0.7ms)  SELECT "events".* FROM "events" WHERE (start_date &gt;= '2015-02-20' OR end_date &gt;= '2015-02-20') AND (location_id IS NULL)
   =&gt; #&lt;ActiveRecord::Relation [#&lt;Event id: 58, name: "BENNY GREB CLINIC w Hard Rock Cafe Warszawa", start_date: "2015-02-21", end_date: nil, location: "Hard Rock Cafe Warsaw,ul. Złota 59,Warsaw,Poland", logo_url: "https://fbcdn-sphotos-c-a.akamaihd.net/hphotos-ak-...", website: "", facebook: "https://www.facebook.com/events/535924839876600", created_at: "2015-02-19 17:38:29", updated_at: "2015-02-19 17:38:29", logo_file_file_name: nil, logo_file_content_type: nil, logo_file_file_size: nil, logo_file_updated_at: nil, location_id: nil&gt;]&gt; 
  </code></pre>
  
  <p>So <code>location: "Hard Rock Cafe Warsaw,ul. Złota 59,Warsaw,Poland"</code></p>
  
  <p>But when I do:</p>
  
  <pre><code>2.2.0 :002 &gt; a.first.location
  </code></pre>
  
  <p>I get</p>
  
  <pre><code> =&gt; nil 
  </code></pre>
  
  <p>Why?</p>