Update THANKS.
diff --git a/THANKS b/THANKS
index bb386a5..6835db4 100644
--- a/THANKS
+++ b/THANKS
@@ -33,6 +33,7 @@
   - Bill Glessner
   - Jason Gorski
   - Juan Manuel Guerrero
+  - Diederik de Haas
   - Joachim Henke
   - Christian Hesse
   - Vincenzo Innocente