Add Backblaze CORS settings

Backblaze-CORS-settings.md

@@ -0,0 +1,30 @@
+To enable client side file uploads on a B2 bucket, CORS rules must be set.
+
+
+
+    b2 bucket update --cors-rules "$(<~/cors-rules.json)" fp-dev
+
+```json5
+  // cors-rules.json
+  [
+        {
+            "allowedHeaders": [
+                "*"
+            ],
+            "allowedOperations": [
+                "s3_head",
+                "s3_put",
+                "s3_get"
+            ],
+            "allowedOrigins": [
+                "https://futureporn.net"
+            ],
+            "corsRuleName": "downloadFromAnyOriginWithUpload",
+            "exposeHeaders": [
+                "etag"
+            ],
+            "maxAgeSeconds": 3600
+        }
+    ]
+```
+