def unvote
      security_transgression_unless @comment.can_be_voted_on_by?(@user)

      @comment.unvote voter: @user

      respond_to do |format|
        format.html { redirect_to @thread }
        format.js { render :vote }
      end
    end
def unvote
      security_transgression_unless @comment.can_be_voted_on_by?(@user)

      @comment.unvote voter: @user

      respond_to do |format|
        format.html { redirect_to @thread }
        format.js { render :vote }
      end
    end
PUT /comments/1/unvote