refactored genetic

genes.rb

class Chromosome
  attr_accessor :bit_string, :fitness

  def initialize length, bit_string = nil
    @length = length

    if bit_string.nil?
      generate_random length
    else
      @bit_string = bit_string
    end
  end 

  def generate_random length
    length.times do
      @bit_string ||= ''
      @bit_string << rand(2).to_s
    end
  end

  def self.get_random_chromosomes length, number
    number.times do
      @res ||= []
      @res << Chromosome.new(length)
    end 

    set_fitnesses res
    res
  end
end