Initial commit of Docker role

Change-Id: I7326a4e1c784b0e27294d9ce11beb4be25386192
diff --git a/defaults/main.yml b/defaults/main.yml
new file mode 100644
index 0000000..af54b70
--- /dev/null
+++ b/defaults/main.yml
@@ -0,0 +1,7 @@
+---
+# docker defaults/main.yml
+#
+# SPDX-FileCopyrightText: © 2020 Open Networking Foundation <support@opennetworking.org>
+# SPDX-License-Identifier: Apache-2.0
+
+docker_version: "19.03"