easy sorting on ruby

mysort.rb

class Array
  def my_sort!
    1.upto(size-1) do |i|
      i.downto(1) do |j|
        swap!(j, j-1) if less?(j, j-1)
      end
    end
  end

  def swap!(ind1, ind2)
    self[ind1], self[ind2] = self[ind2], self[ind1]
  end

  def less?(ind1, ind2)
    self[ind1] < self[ind2]
  end
end

a = [10, 2030, 300, 9]
a.my_sort!
p a