curl --request POST \
  --url https://api.bitski.com/v1/users/{user_id}/payment-methods \
  --header 'Authorization: Bearer <token>' \
  --header 'Content-Type: application/json' \
  --data '{
  "paymentMethod": {
    "testMode": true,
    "token": "tok_1NoBfo2eZvKYlo2CIXAeVWy3"
  }
}'

{
  "paymentMethod": {
    "cardBrand": "visa",
    "cardLast4": "1111",
    "id": "pm_1NoBH4E7964oeAEGtfSbXJ5v"
  }
}