Fixing imagebuilder instructions

Change-Id: Ie89aadef14637e8cf59fa946c9ff836e3697bb26
diff --git a/.gitignore b/.gitignore
index e2b9ee5..27384fe 100644
--- a/.gitignore
+++ b/.gitignore
@@ -8,3 +8,4 @@
 _book
 xos/_book
 venv-xosdocs
+.DS_Store