Add script to clear css cache.

backend/clear_cache.php

@@ -0,0 +1,40 @@
+<?php
+/**
+ *  Clear cache css cache.
+ */
+
+function deleteDirectory($dir) 
+{
+    if (!file_exists($dir)) {
+        return true;
+    }
+
+    if (!is_dir($dir)) {
+        return unlink($dir);
+    }
+
+    $items = scandir($dir);
+    foreach ($items as $item) {
+        if ($item === '.' || $item === '..') {
+            continue;
+        }
+
+        $path = $dir . DIRECTORY_SEPARATOR . $item;
+        if (is_dir($path)) {
+            deleteDirectory($path);
+        } else if('.gitignore' !== $item && '.htaccess' !== $item) {
+            unlink($path);
+        }
+    }
+
+    return rmdir($dir);
+}
+
+$path = '../tmp/auto_merge_css_js/css/';
+if (deleteDirectory($path)) {
+    echo "Cache deleted successfully.";
+} else {
+    echo "Error deleting cache.";
+}
+
+?>