Clarify App token usage (#567)

* Update index.md

* Enhance documentation for App Token authentication

Added example for using App Token authentication with curl.

* Update index.md

* Update index.md typoz

Author: Its-Just-Nans

versioned_docs/version-4.0/dev/server/apis/http/graph/index.md

@@ -63,4 +63,16 @@ For development purposes the examples in the developer documentation use Basic A
 
 To authenticate with a Bearer token or OpenID Connect access token replace the `-u user:password` Basic Auth option of curl with a `-H 'Authorization: Bearer <token>'` header. A `<token>` can be obtained by copying it from a request in the browser, although it will time out within minutes. To automatically refresh the OpenID Connect access token an ssh-agent like solution like [oidc-agent](https://github.com/indigo-dc/oidc-agent) should be used. The graph endpoints that support a preconfigured token can be found in the [API specification](https://github.com/opencloud-eu/libre-graph-api)
 
+#### Authorization with App token
+
+Users can create an App Token in their Open Cloud interface. This token can be used to authenticate a user using the Account Name for the username and the token as password. Here is an example using curl
+
+```sh
+curl 'https://cloud.opencloud.test/graph/v1.0/me' -H 'accept: application/json' -u 'accountname:the generated app token'
+
+# or using the Authentification Basic Header
+# Authentification: Basic BASE64(username + ':' + app token)
+curl 'https://cloud.opencloud.test/graph/v1.0/me' -H 'accept: application/json' -H 'Authorization: Basic YWNjb3VudG5hbWU6dGhlIGdlbmVyYXRlZCBhcHAgdG9rZW4='
+```
+
 ## Resources