def diff
      @diff = UiChanged::Screenshot.find(params[:diff_id])
      @control = UiChanged::Screenshot.find(@diff.control_id)
      @test = UiChanged::Screenshot.find(@diff.test_id)
    end
def diff
      @diff = UiChanged::Screenshot.find(params[:diff_id])
      @control = UiChanged::Screenshot.find(@diff.control_id)
      @test = UiChanged::Screenshot.find(@diff.test_id)
    end
GET /screenshots/diff