Refactor logic from gerrit.sh into gerrit/filters.  Add modular usage/help

Change-Id: I2ff1d0eda2bb7e80dab8d345721f39c621357774
diff --git a/makefile b/makefile
new file mode 100644
index 0000000..262c76f
--- /dev/null
+++ b/makefile
@@ -0,0 +1,15 @@
+# -*- makefile -*-
+## -----------------------------------------------------------------------
+## -----------------------------------------------------------------------
+
+common-sh := lf/onf-common/common.sh
+
+all : $(common-sh)
+
+## -----------------------------------------------------------------------
+## Intent: On-demand submodule checkout
+## -----------------------------------------------------------------------
+$(common-sh) :
+	git submodule update --init --recursive
+
+# [EOF]