Update doc ACKS.
diff --git a/Doc/ACKS.txt b/Doc/ACKS.txt
index 7344cf8..08ab070 100644
--- a/Doc/ACKS.txt
+++ b/Doc/ACKS.txt
@@ -21,6 +21,7 @@
    * Chris Barker
    * Don Bashford
    * Anthony Baxter
+   * Alexander Belopolsky
    * Bennett Benson
    * Jonathan Black
    * Robin Boerdijk