Architecture Kata "Vocabulary of the day"

Develop an Internet service with which you can have a vocabulary word sent to you every day.

The user registers with their email address and a time period. If he confirms the registration via a link in a subsequent email, he will receive a vocabulary including translation by email from Monday to Friday in the specified period (default: 9-15h), e.g.

To: petersalz@web.de
Subject: Vocabulary of the day #123
Text:
English: to kill two birds with a stone
German: to kill two birds with one stone

At the end of the email, they will find a link to stop the mailing. If he does this, he deregisters from the service. It is not possible to change the email address.

The transmissions are counted per participant. Vocabulary is not sent out more than once.

The service only offers one language.