add and update license

rb/glicko2.rb

@@ -2,7 +2,7 @@
 
 #
 #
-# Copyright (c) 2004 Stephen Waits
+# Copyright (c) 2013 Stephen Waits
 # 
 # This software is provided 'as-is', without any express or implied warranty. In
 # no event will the authors be held liable for any damages arising from the use