doc/Contents

--- a/doc/Contents	Fri Apr 20 11:21:33 2007 +0200
+++ b/doc/Contents	Fri Apr 20 11:21:34 2007 +0200
@@ -2,6 +2,7 @@
   tutorial        Tutorial on Isabelle/HOL
   isar-overview   Tutorial on Isar
   locales         Tutorial on Locales
+  classes         Tutorial on Type Classes
   functions       Tutorial on Function Definitions
   codegen         Tutorial on Code Generation
   axclass         Tutorial on Axiomatic Type Classes