Test container with an actual site

[mbrgm]

The container is running, but has yet to be tested with an actual site. Things
to be tested are:

• Creation of and viewing comments
• Moderation
• SMTP configuration
• Inspect an attached data-volume container for the comment data

[mbrgm]

Moderation works with SMTP configured. With general.notify = stdout, the activation link is not logged to stdout, contrary to what the docs say. I opened isso-comments/isso#138 to address this.