Added the Optimization Framework OSDF doc folder

Issue-ID: OPTFRA-65
Change-Id: Ie71fc7a72996bff6312630281a50778fa3da418b
Signed-off-by: Sastry Isukapalli <sastry@research.att.com>
diff --git a/.gitmodules b/.gitmodules
index b2a110e..c07b20d 100644
--- a/.gitmodules
+++ b/.gitmodules
@@ -276,3 +276,6 @@
 	url = ../ui/dmaapbc
 	branch = .
 	ignore = dirty
+[submodule "docs/submodules/optf/osdf.git"]
+	path = docs/submodules/optf/osdf.git
+	url = ../optf/osdf