Not saying what @senny is wrong, but I think we want to change this to schema.rb support even database specific things. I think it is not so common people change database. They may have support to multiple database, but if they choose to use json fields for example they know it will only work with PostgreSQL. I don't think we should force people to use structure.sql even if they know something will work only in one database.

We may require structure.sql if people is using something we don't have support like foreign keys, but not for things we do support like `json`, `jsonb,`, `array` and etc.