Add some PHP-CLI scripts to be run as cronjobs

common/scripts/clean_garbage_files.php

@@ -0,0 +1,25 @@
+<?php
+
+/**
+ * This script deletes files that were not properly uploaded.
+ * 
+ * Files can remain in an invalid status for two reasons: 1) a user abandons
+ * a document or comment after uploading files; or 2) a chunked upload is
+ * aborted without the server having any opportunity to clean it up.
+ * These files can obviously take up a lot of disk space. In order to prevent
+ * them from accumulating too much, you should run this script at least once
+ * every few days.
+ */
+require_once __DIR__ . '/common.php';
+
+// Delete garbage files older than this number of days.
+$days = 10;
+
+// Initialize the exit status.
+$exit_status = 0;
+
+// Set the exit status if there were any errors.
+if ($exit_status != 0)
+{
+	exit($exit_status);
+}