Ignore all *.dat files
diff --git a/.hgignore b/.hgignore
index c0447dd..9d35255 100644
--- a/.hgignore
+++ b/.hgignore
@@ -1,6 +1,7 @@
 syntax: glob
 
 *.pyc
+*.dat
 .*.swp
 */.git/*
 .gitignore