added a note about AAD token for Azure DevOps repository

README.md

@@ -51,7 +51,7 @@ The Azure DevOps setup consists of the several steps, described in the next sect
 Because we have several pipelines, the it's makes sense to define [variable group](https://docs.microsoft.com/en-us/azure/devops/pipelines/library/variable-groups) to store the data that are necessary for execution of tests & deployment of the code.  We need following configuration properties for execution of our pipelines:
 
 * `databricks_host` - the [URL of your workspace](https://docs.databricks.com/workspace/workspace-details.html#workspace-instance-names-urls-and-ids) where tests will be executed (host name with `https://`, without `?o=`).
-* `databricks_token` - personal access token for executing commands against the workspace.  Mark this variable as private!
+* `databricks_token` - personal access token for executing commands against the workspace.  Mark this variable as private!  Note that if you're using Azure DevOps to host repository, then you need to use AAD token instead.
 * `cluster_id` - the ID of the cluster where tests will be executed.
 
 The name of the variable group is used in the [azure-pipelines.yml](azure-pipelines.yml). By default its name is "Nutter Testing".  Change the [azure-pipelines.yml](azure-pipelines.yml) if you use another name for variable group.