curl --location '/availability/calendar?from=undefined&to=undefined' \
--header 'Authorization: Bearer <token>'[
{
"id": 0,
"type": "APPOINTMENT",
"title": "string",
"description": "string",
"status": "string",
"start": "2019-08-24T14:15:22.123Z",
"end": "2019-08-24T14:15:22.123Z"
}
]