Inline some content for the HPA walkthrough, since the original files have been removed (#7414)

Author: cimomo

docs/tasks/run-application/horizontal-pod-autoscale-walkthrough.md

@@ -29,8 +29,25 @@ See the [Horizontal Pod Autoscaler user guide](/docs/tasks/run-application/horiz
 ## Step One: Run & expose php-apache server
 
 To demonstrate Horizontal Pod Autoscaler we will use a custom docker image based on the php-apache image.
-The Dockerfile can be found [here](/docs/user-guide/horizontal-pod-autoscaling/image/Dockerfile).
-It defines an [index.php](/docs/user-guide/horizontal-pod-autoscaling/image/index.php) page which performs some CPU intensive computations.
+The Dockerfile has the following content:
+
+```
+FROM php:5-apache
+ADD index.php /var/www/html/index.php
+RUN chmod a+rx index.php
+```
+
+It defines an index.php page which performs some CPU intensive computations:
+
+```
+<?php
+  $x = 0.0001;
+  for ($i = 0; $i <= 1000000; $i++) {
+    $x += sqrt($x);
+  }
+  echo "OK!";
+?>
+```
 
 First, we will start a deployment running the image and expose it as a service: