How to create PostgreSQL database?

While installing zammad, I got the following and a lot more similar errors:

# apt install zammad
....
# Clear cache...
# database.yml found. Updating db...
rake aborted!
ActiveRecord::NoDatabaseError: We could not find your database: zammad. Which can be found in the database configuration file located at config/database.yml. (ActiveRecord::NoDatabaseError)

To resolve this issue:

- Did you create the database for this app, or delete it? You may need to create your database.
- Has the database name changed? Check your database.yml config has the correct database name.

To create your database, run:

        bin/rails db:create

Am I wrong but the package should create the database itself, or do I have to create it in advance?