Missing documentation for the modules attribute when creating a distribution set

[zyga]

Looking at https://www.eclipse.org/hawkbit/rest-api/distributionsets-api-guide/#_post_rest_v1_distributionsets one can see how to create a distribution set by POSTing to the /rest/v1/distributionsets. The examples show how one can refer to software modules by presenting a list of {"id": 123} objects under the modules attribute but this essential attribute is not documented.