Detect required schema changes

[sebschrader]

If schema related options are changed, the user has to be aware that he has to recreate the database or perform the schema changes manually.

This is error prone. At least a warning/error mechanism should be present, that informs the user.

An automatic schema change would be the greatest thing however, but I don't know if this is doable. Maybe alembic could help. Maybe @lukasjuhrich can give some tips.