curl --request POST \
  --url https://api.projectcor.com/v1/contracts/{contract_id}/users \
  --header 'Authorization: Bearer <token>' \
  --header 'Content-Type: application/json' \
  --data '
{
  "users": [
    {
      "id": 123,
      "dates": [
        {
          "start": "2026-01-01",
          "end": "2026-02-01"
        },
        {
          "start": "2026-01-01",
          "end": "2026-02-02"
        }
      ]
    }
  ]
}
'

{
  "status": "partial_success",
  "company_id": 999,
  "contract_id": 777,
  "records_received": 8,
  "records_created": 2,
  "records_rejected": 8,
  "assigned": [
    {
      "id": 501,
      "user_id": 88001,
      "start_date": "2024-01-01T00:00:00.000Z",
      "end_date": "2024-12-31T00:00:00.000Z"
    },
    {
      "id": 502,
      "user_id": 88001,
      "start_date": "2024-03-01T00:00:00.000Z",
      "end_date": "2024-06-30T00:00:00.000Z"
    }
  ],
  "errors": [
    {
      "id": 88001,
      "dates": [
        {
          "start": "2024-06-01",
          "end": "2024-04-01",
          "message": "Date malformatted. Start date must be before end date"
        },
        {
          "start": null,
          "end": null,
          "message": "Date malformatted"
        },
        {
          "start": "2024-02-01",
          "end": null,
          "message": "Date malformatted. Start and end date are required"
        },
        {
          "start": "not-a-date",
          "end": "2024-12-31",
          "message": "Invalid date"
        },
        {
          "start": "1990-01-01",
          "end": "1990-06-30",
          "message": "Invalid contract periods. Range must be within contract start and end dates"
        }
      ],
      "message": "Partial success. Some dates were rejected"
    },
    {
      "id": "hello",
      "dates": [
        {
          "start": "2024-01-01",
          "end": "2024-12-31"
        }
      ],
      "message": "User malformatted"
    },
    {
      "id": 88002,
      "start": "2024-01-01",
      "end": "2024-12-31",
      "message": "Legacy format detected. Use \"dates\" array instead of \"start\" and \"end\" fields"
    },
    {
      "id": 88003,
      "dates": [],
      "message": "Date malformatted or empty"
    },
    {
      "id": 88004,
      "dates": [
        {
          "start": "2024-07-01",
          "end": "2024-07-01",
          "message": "Date malformatted. Start date must be before end date"
        }
      ],
      "message": "Dates are malformatted or empty"
    },
    {
      "id": 88005,
      "dates": [
        {
          "start": null,
          "end": null,
          "message": "Date malformatted"
        }
      ],
      "message": "Partial success. Some dates were rejected"
    },
    {
      "id": 999999,
      "dates": [
        {
          "start": "2024-01-01",
          "end": "2024-12-31"
        }
      ],
      "message": "User malformatted"
    },
    {
      "id": 88005,
      "dates": [
        {
          "start": "2024-01-01",
          "end": "2024-06-30"
        }
      ],
      "message": "User malformatted"
    }
  ]
}