add vercel script for determining deployment skipping (#2277)

docs/vercel.sh

@@ -0,0 +1,13 @@
+#!/bin/bash
+
+git diff --quiet HEAD^ HEAD ./
+has_changes=$?
+echo ">> Diff status $has_changes"
+
+if [[ $VERCEL_GIT_COMMIT_REF == "master" ]] || [ $has_changes == 1 ]; then
+  echo ">> Proceeding with deployment."
+  exit 1;
+else
+  echo ">> Skipping deployment."
+  exit 0;
+fi