Authorization: Bearer ********************{
"referral_code": "string"
}curl --location --request POST '/api/v2/ktties/join-by-referral-code' \
--header 'Authorization: Bearer <token>' \
--header 'Content-Type: application/json' \
--data-raw '{
"referral_code": "string"
}'{
"kttiId": "string"
}