Add script for verifying docs without entry

.travis.yml

@@ -14,3 +14,4 @@ install:
 script:
 - go test -v k8s.io/kubernetes.github.io/test
 - $GOPATH/bin/md-check --root-dir=$HOME/gopath/src/k8s.io/kubernetes.github.io
+- ./verify-entry-toc.sh

skip_toc_check.txt

@@ -0,0 +1,3 @@
+# Put files you want to skip table of contents entry check here:
+docs/search.md
+docs/sitemap.md

verify-entry-toc.sh

@@ -0,0 +1,20 @@
+#!/bin/bash
+
+no_entry=false
+
+# Verify all docs/.../*.md files are referenced in at least one of _data/*.yml
+# files. Skip checking files in skip_toc_check.txt
+for file in `find docs -name "*.md" -type f`; do 
+  if ! grep -q "${file}" skip_toc_check.txt; then
+    path=${file%.*}
+    if ! grep -q "${path}" _data/*.yml; then
+      echo "Error: ${file} doesn't have an entry in the table of contents under _data/*.yml" 
+      no_entry=true
+    fi
+  fi
+done
+
+if ${no_entry}; then 
+  echo "Found files without entries. For how to fix it, see http://kubernetes.io/docs/contribute/write-new-topic/#creating-an-entry-in-the-table-of-contents"
+  exit 1
+fi