curl --request POST \
--url https://backend.testeswaffle.org/referrals/subscribe \
--header 'Content-Type: application/json' \
--data '{
"referrer_id": "usr_123456789",
"referred_email": "indicado@exemplo.com",
"referred_name": "Carlos Indicado",
"newsletter": "thenews",
"campaign": "janeiro_2024"
}'