RCR 327: true and false should be comparable with <=>

 >> [true, false, true].sort                                                     
 NoMethodError: undefined method `<=>' for true:TrueClass                        
  from (irb):1:in `sort'                                                         
  from (irb):1                                                                   

Makes me confused...

 >> [true, false, true].sort                                                     
 => [false, true, true]                                                          

or

 >> [true, false, true].sort                                                     
 => [true, true, false]                                                          

 class FalseClass
   def <=>(other)
     other ? -1 : 0
   end
 end
 class TrueClass
   def <=>(other)
     other ? 0 : 1
   end
 end

Or the other way around. I'm sure there's a more elegant implementation.