Update README

Author: arashnd

README.md

@@ -31,6 +31,7 @@ AzureBlob supports managed identities on :
 - App Service
 - Azure Functions (Untested but should work)
 - Azure Containers (Untested but should work)
+- Azure AD Workload Identity (AKS/K8s)
 
 AKS support will likely require more work. Contributions are welcome.
 
@@ -46,6 +47,20 @@ prod:
   principal_id: 71b34410-4c50-451d-b456-95ead1b18cce
 ```
 
+#### Azure AD Workload Identity (AKS/K8s)
+
+ActiveStorage config example:
+
+```
+prod:
+  service: AzureBlob
+  container: container_name
+  storage_account_name: account_name
+```
+
+> uses `AZURE_CLIENT_ID`, `AZURE_TENANT_ID` and `AZURE_FEDERATED_TOKEN_FILE` environment variables, made available by AKS cluster when Azure AD Workload Identity is set up properly.
+
+
 ### Azurite
 
 To use Azurite, pass the `storage_blob_host` config key with the Azurite URL (`http://127.0.0.1:10000/devstoreaccount1` by default)