how to implement insert sort using ruby

insert_sort.rb

# insert sort using ruby

def insert_sort(array)
	(1..array.size-1).each do |index|
		key = array[index]
		j = index - 1
		while key < array[j] && j >= 0
			array[j + 1] = array[j]	
			j = j-1
		end #while
		array[j+1] = key
	end #for
	array
end #insert_sort

array = [3, 7, 5, 2, 1, 9, 8]
puts insert_sort(array)