CONTRIBUTORS

--- a/CONTRIBUTORS	Tue Apr 24 14:17:57 2018 +0000
+++ b/CONTRIBUTORS	Tue Apr 24 14:17:58 2018 +0000
@@ -6,6 +6,9 @@
 Contributions to this Isabelle version
 --------------------------------------
 
+* May 2018: Florian Haftmann
+  Consolidation of string-like types in HOL.
+
 * March 2018: Florian Haftmann
   Abstract bit operations push_bit, take_bit, drop_bit, alongside
   with an algebraic foundation for bit strings and word types in