curl --request POST \
  --url https://api.meetcampfire.com/rr/api/v1/contracts/{contract_id}/tier-price-overrides \
  --header 'Authorization: <api-key>' \
  --header 'Content-Type: application/json' \
  --data '
{
  "tier": 123,
  "contract": 123,
  "price": 0,
  "percentage": 0,
  "source": "manual",
  "integration_name": "<string>",
  "external_reference": "<string>",
  "notes": "<string>"
}
'

{
  "id": 123,
  "tier": 123,
  "tier_name": "<string>",
  "contract": 123,
  "deal_name": "<string>",
  "usage_group_id": 123,
  "usage_group_name": "<string>",
  "created_at": "2023-11-07T05:31:56Z",
  "last_modified_at": "2023-11-07T05:31:56Z",
  "price": 0,
  "percentage": 0,
  "source": "manual",
  "integration_name": "<string>",
  "external_reference": "<string>",
  "notes": "<string>"
}