added `f` for 1 byte FizzBuzz because Hexagony has such feature

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@63475 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

golf_prelude.rb

@@ -50,6 +50,11 @@ class Object
     puts "#{a}ello, #{b}orld#{c}"
   end
 
+  def f(m = 100)
+    1.upto(m){|n|puts'FizzBuzz
+'[i=n**4%-15,i+13]||n}
+  end
+
   alias say puts
 
   def do_while