title: Does adding a new object in a has_one relationship, not update the association?
body: <p>I have 2 models, an example:</p>
  
  <pre><code>class Report ...
    belongs_to :answer_sheet
  end
  
  class AnswerSheet ...
    has_one :report
  end
  </code></pre>
  
  <p>When I do a:</p>
  
  <pre><code>@answersheet.report = Report.create(:data =&gt; 'bleah')
  @answersheet.save
  
  # and then create another report and assign it to the same @answersheet
  # assuming at this stage @answersheet is already reloaded
  
  @answersheet.report = Report.create(:data =&gt; 'new data')
  @answersheet.save
  
  
  # (irb) @answersheet.report returns the first report with the data 'bleah' and not
  # the one with the new data.
  </code></pre>
  
  <p>Is this supposed to be the correct behavior?</p>
  
  <p>If I want to update the association to the later report, how should I go about doing it?</p>