diff --git a/Config/AsseticResource.php b/Config/AsseticResource.php
index <HASH>..<HASH> 100644
--- a/Config/AsseticResource.php
+++ b/Config/AsseticResource.php
@@ -47,4 +47,29 @@ class AsseticResource implements SymfonyResourceInterface
     {
         return $this->resource;
     }
+
+    public function exists()
+    {
+        return true;
+    }
+
+    public function getId()
+    {
+        return md5('assetic'.$this->resource);
+    }
+
+    public function getModificationTime()
+    {
+        return -1;
+    }
+
+    public function serialize()
+    {
+        return serialize($this->resource);
+    }
+
+    public function unserialize($serialized)
+    {
+        $this->resource = unserialize($serialized);
+    }
 }
Updated the AsseticResource to the new interface

Closes #<I>