Merge pull request #50291 from douglaslMS/adf-batch-perms

Added permissions info that answers issue 12253.

Author: PRMerger12

articles/data-factory/transform-data-using-dotnet-custom-activity.md

@@ -11,7 +11,7 @@ ms.workload: data-services
 ms.tgt_pltfrm: na
 ms.devlang: na
 ms.topic: conceptual
-ms.date: 01/16/2018
+ms.date: 08/29/2018
 ms.author: douglasl
 
 ---
@@ -105,6 +105,10 @@ The following table describes names and descriptions of properties that are spec
 | referenceObjects      | An array of existing Linked Services and Datasets. The referenced Linked Services and Datasets are passed to the custom application in JSON format so your custom code can reference resources of the Data Factory | No       |
 | extendedProperties    | User-defined properties that can be passed to the custom application in JSON format so your custom code can reference additional properties | No       |
 
+## Custom activity permissions
+
+The custom activity sets the Azure Batch auto-user account to *Non-admin access with task scope* (the default auto-user specification). You can't change the permission level of the auto-user account. For more info, see [Run tasks under user accounts in Batch | Auto-user accounts](../batch/batch-user-accounts.md#auto-user-accounts).
+
 ## Executing commands
 
 You can directly execute a command using Custom Activity. The following example runs the "echo hello world" command on the target Azure Batch Pool nodes and prints the output to stdout.