curl --request POST \
  --url https://api.meetcampfire.com/rr/api/v1/contracts/{contract_id}/milestones \
  --header 'Authorization: <api-key>' \
  --header 'Content-Type: application/json' \
  --data '
{
  "contract": 123,
  "product": 123,
  "product_bundle": 123,
  "milestone_name": "<string>",
  "milestone_date": "2023-12-25",
  "amount": 0,
  "description": "<string>",
  "department": 123
}
'

{
  "id": 123,
  "customer": 123,
  "contract": 123,
  "product": 123,
  "product_bundle": 123,
  "product_name": "<string>",
  "product_bundle_name": "<string>",
  "milestone_name": "<string>",
  "milestone_date": "2023-12-25",
  "amount": 0,
  "description": "<string>",
  "department": 123,
  "department_name": "<string>",
  "tags": [
    {
      "id": 123,
      "group_name": "<string>",
      "parent_name": "<string>",
      "parent": 123,
      "is_deleted": false,
      "deleted_at": "2023-11-07T05:31:56Z",
      "name": "<string>",
      "created_at": "2023-11-07T05:31:56Z",
      "last_modified_at": "2023-11-07T05:31:56Z",
      "customer": 123,
      "group": 123
    }
  ],
  "revenue_transaction_id": 123,
  "created_at": "2023-11-07T05:31:56Z",
  "last_modified_at": "<string>",
  "is_deleted": false,
  "deleted_at": "2023-11-07T05:31:56Z"
}