check for cover image

covo_card.haml

  %header{class: topic.cover_image? ? 'coverimage' : ''}
    -if topic.cover_image?
      %figure.img-canvas-small
        =image_tag(comment.topic.cover_image)
  
    -# I want this execute seperately, but nested in header
    %article
      %h2
        -if comment.conversation.subject?
          %a.title{ href: conversation_path(comment.conversation, anchor: comment.id.to_s), 'data-pjax' => '#container' }
            =comment.conversation.subject
        -else
          %a.title{ href: conversation_path(comment.conversation, anchor: comment.id.to_s), 'data-pjax' => '#container' }
            =comment.topic.title
    -# end nesting