class07: add document link

classes/class07/meta.json

@@ -2,6 +2,6 @@
     "name": "Class 07 - Lateral Movement",
     "id": "class-07",
     "description": "The seventh class focuses on lateral movement, virtualization and threat intelligence. Please open the Google document provided to all registered students and follow the document.",
-    "google_doc_url": "",
+    "google_doc_url": "https://docs.google.com/document/d/1SB9yzvTTLzN-Re-sgegL2xsgimOM9g2SvDauj_K-WJo/edit?usp=sharing",
     "yt_recording_url": ""
 }