Ignore cover database

Change-Id: I327f8e9e9717081d9379b4e4cb22daa4d777d5b3
diff --git a/.gitignore b/.gitignore
index 417d50c..8291b06 100644
--- a/.gitignore
+++ b/.gitignore
@@ -16,6 +16,7 @@
 MYMETA*
 Makefile
 pm_to_blib
+cover_db
 nytprof.out
 nytprof
 \#*#