Add myself to Doc/ACKS.txt
diff --git a/Doc/ACKS.txt b/Doc/ACKS.txt
index 08ab070..337a57a 100644
--- a/Doc/ACKS.txt
+++ b/Doc/ACKS.txt
@@ -145,6 +145,7 @@
    * Harri Pasanen
    * Bo Peng
    * Tim Peters
+   * Benjamin Peterson
    * Christopher Petrilli
    * Justin D. Pettit
    * Chris Phoenix