Add dockerfile for MDG's

- Added option to installer to use specfic docker build tag

Change-Id: Ia6cf6316c6fb84a18ecdbaf98747a95c20ce2f0b
Signed-off-by: Mike Marchetti <mmarchetti@sandvine.com>
diff --git a/docker/.gitignore b/docker/.gitignore
new file mode 100644
index 0000000..567609b
--- /dev/null
+++ b/docker/.gitignore
@@ -0,0 +1 @@
+build/