title: Rails Papertrail - display who Was Responsible for last change
body: <p>I'm using Devise and Papertrail and would like to display which user made the most recent update (<a href="https://github.com/airblade/paper_trail#finding-out-who-was-responsible-for-a-change" rel="nofollow">documentation link</a>). </p>
  
  <p>In controller:</p>
  
  <pre><code>  def show
      # @history = @person.versions.last 
      @last_change = @person.versions.last
      @user_who_made_the_change = User.find @last_change.whodunnit.to_i
    end
  </code></pre>
  
  <p>In show page</p>
  
  <pre><code> &lt;%= @user_who_made_the_change %&gt;
  </code></pre>
  
  <p>However I get the resulting error:
  <strong>undefined method `whodunnit' for nil:NilClass</strong></p>
  
  <p>in <em>app/controllers/people_controller.rb:15:in `show'</em></p>
  
  <p>Any help would be much appreciated, thanks</p>