Ignore .DS_STORE files in git.

Test: manual
Change-Id: I09bad9a253b78a0c5b1b512ebd689d82ba9ad253
diff --git a/.gitignore b/.gitignore
index dd5dda7..98fff82 100644
--- a/.gitignore
+++ b/.gitignore
@@ -20,6 +20,7 @@
 NOTICE
 README.md
 README-wear.txt
+.DS_STORE
 
 # Libraries used by the app
 # Can explicitly add if we want, but shouldn't do so blindly.  Licenses, bloat, etc.