# req-012

As a user, I want to record a beer transaction in Schist by SMS, so that my
purchase of beer in cash when I have access to my phone is recorded as a beer
transaction.

Source: req-011

Satisfied by: req-043, req-044, req-045, ass-010, req-046, req-047

## Use case

Trigger: The user buys a beer.

1. If Schist is not in the user's phone contacts, go to req-013.
2. If the user doesn't know how to form the right command, they use the help
   interface until they do know how to form the right command.
3. The user sends an SMS to Schist.
4. If the command is invalid or incorrect, Schist sends help text to the user,
   then go to step 3.
5. Schist inserts a beer transaction into Schist's database.
6. Schist sends an OK response to the user.