exchange-rate-sender https://www.tcmb.gov.tr/kurlar/today.xml https://sendgrid.com/docs/for-developers/sending-email/api-getting-started/#send-your-email-using-the-api https://medium.com/@tugsanunlu/sendgrid-api-ile-e-posta-g%C3%B6nderimi-30d3536edba2