def color=(color)
      each_with_index do | cell, index |
        cell.color = color.is_a?(Array) ? color[index] : color
      end
    end
def color=(color)
      each_with_index do | cell, index |
        cell.color = color.is_a?(Array) ? color[index] : color
      end
    end
sets the color for every cell in this row