TIL, 2017-06-01
- Bash variable assignments:
HELLO=world, $HELLO, local HELLO=world. request.user_agent.- Requests: Always start with a hash.
- Non-nullable values: Do the migration, update everything, then set the column to not null.
- Rails cascade: Drop dependent objects.
- No need to store if notification will be allowed for the token, let the front-end handle it.