useful methods additions for ruby core classes

ruby_method_adding

class Numeric
  def roundup(nearest=10)
    self % nearest == 0 ? self : self + nearest - (self % nearest)
  end
  def rounddown(nearest=10)
    self % nearest == 0 ? self : self - (self % nearest)
  end
end 
puts 2.roundup    #=> 10
puts 23.roundup   #=> 30
puts 20.roundup   #=> 20
puts 45.roundup   #=> 50
puts 156.roundup  #=> 160 
puts 156.34.roundup   #=> 160.0
puts 16.34.roundup    #=> 20.0
puts 81.1234.roundup  #=> 90.0

class String
  def to_range
    self.split('..').inject { |s,e| s.to_i..e.to_i }
  end
end
"0..230".to_range
#=> 0..230