class Integer
  # Check whether the integer is evenly divisible by the argument.
  #
  #   0.multiple_of?(0)  #=> true
  #   5.multiple_of?(5)  #=> false
  #   10.multiple_of?(2) #=> true
  def multiple_of?(number)
    number != 0 ? self % number == 0 : zero?
  end
end