Started gitbook in docs folder

Change-Id: Ifda129c3202855bba16a7c77e35b4351c9773655
diff --git a/.gitignore b/.gitignore
index 73ddaa1..79d5503 100644
--- a/.gitignore
+++ b/.gitignore
@@ -31,4 +31,5 @@
 containers/xos/local_certs.crt
 containers/xos/tmp.chameleon/
 containers/xos/BUILD/
-venv-xos/
\ No newline at end of file
+venv-xos/
+_book/