CKAN version
2.8

Describe the bug
It is not possible to determine a users ID when connecting through the API. In my opinion, this should be the default behavior of user_show, but the documentation states that either the id or the user_obj parameter must be given. I think it would be user-convenient to change this default behavior.

Steps to reproduce
Connect via API using an API key and call user_show without arguments.

Expected behavior
The information about the currently logged-in user is shown.

Actual behavior

{"help": "https://dmoain.tld/api/3/action/help_show?name=user_show", "success": false, "error": {"message": "Not found", "__type": "Not Found Error"}}