Add some documentation for the WAF bypass URLs (#547)

docs/waf.md

@@ -0,0 +1,33 @@
+# CloudFront WAF
+
+## Overview
+
+This project is hosted behind a CloudFront Web Application Firewall (WAF).
+
+
+## File uploads
+
+This firewall causes some issues with users who are uploading files, this means that we need to bypass the WAF on any URLs that are used for file uploads.
+
+Below is a list of all the known URLs that should be bypassed:
+
+- `/admin/media/audio/add/`
+- `/admin/media/audio/chooser/upload/`
+- `/admin/media/audio/chooser/create/`
+- `/admin/media/audio/multiple/add/`
+- `/admin/media/edit/{MEDIA_ID}/` where `{MEDIA_ID}` is an integer
+- `/admin/media/video/add/`
+- `/admin/media/video/chooser/upload/`
+- `/admin/media/video/chooser/create/`
+- `/admin/media/video/multiple/add/`
+- `/admin/documents/edit/{DOCUMENT_ID}/` where `{DOCUMENT_ID}` is an integer
+- `/admin/documents/multiple/add/`
+- `/admin/documents/chooser/upload/`
+- `/admin/documents/chooser/create/`
+- `/admin/images/edit/{IMAGE_ID}/` where `{IMAGE_ID}` is an integer
+- `/admin/images/multiple/add/`
+- `/admin/images/chooser/upload/`
+- `/admin/images/chooser/create/`
+- `/people/{PERSON_UUID}/edit/personal/` where `{PERSON_UUID}` is a UUID string
+
+This has been implemented by adding a custom WAF rule to the CloudFront distribution. This rule is a regular expression that matches the URLs above and bypasses the WAF for them.