curl --request POST \
  --url https://api.nuwebgroup.com/v1/discount-codes/fixed/update \
  --header 'Authorization: Bearer <token>' \
  --header 'Content-Type: application/json' \
  --data '
{
  "id": 1,
  "amount": 1000,
  "maxUsesPerOrder": 2,
  "currencyId": 1,
  "maxUsesPerCustomer": 1,
  "minimumSpend": 1000,
  "saleItems": [
    1,
    2
  ],
  "maximumUses": 100,
  "validFrom": "2021-01-01",
  "validTo": "2021-02-01"
}
'

{
  "data": {
    "type": "discountCodes",
    "id": 1,
    "attributes": {
      "type": "fixed",
      "code": "FIXED10",
      "amount": 1000,
      "applyToNetPrice": false,
      "maxUsesPerOrder": 3,
      "maximumUses": 100,
      "maxUsesPerCustomer": 1,
      "minimumSpend": 1000,
      "validFrom": "2021-11-22T00:00:00.000000Z",
      "validTo": "2021-11-25T00:00:00.000000Z",
      "boxOfficeOnly": false,
      "disabledAt": null,
      "createdAt": "2021-11-22T00:00:00.000000Z",
      "updatedAt": "2021-11-22T00:00:00.000000Z"
    },
    "relationships": {
      "currencies": {
        "data": {
          "type": "currencies",
          "id": 1
        }
      },
      "saleItems": {
        "data": [
          {
            "type": "saleItems",
            "id": 1
          },
          {
            "type": "saleItems",
            "id": 2
          }
        ]
      }
    },
    "links": {
      "self": "http://api.willms.com/v1/discount-codes?id=1"
    }
  },
  "included": [
    {
      "type": "currencies",
      "id": 1,
      "attributes": {
        "name": "Pounds",
        "code": "GBP",
        "symbol": "£",
        "subunit": 2,
        "isCashless": false,
        "isCustom": false,
        "isPrimary": true
      }
    }
  ]
}