Add /user routes to openapi schema

docs/api-usage.md

@@ -8,3 +8,15 @@ For a usage example, see [our Python demo](https://github.com/GSA/notify-python-
 
 An API key can be created at https://notifications-admin.app.cloud.gov/services/YOUR_SERVICE_ID/api/keys. However, in order to successfully send messages, you will need to receive a secret header token from the Notify team.
 
+
+## Using OpenAPI documentation
+
+### Retrieving a bearer token for use
+
+On a mac, run
+
+```
+flask command create-admin-jwt | tail -n 1 | pbcopy
+```
+
+to copy a token usable by the admin UI to your pasteboard. This token will expire in 30 seconds