Automatically generate Knexfile for migrations

Hello,

Please expose migrations directory .wappler/migrations inside the Docker container, as well as an appropriate Knexfile to facilitate automatic migrations.

This will facilitate future automated deployments (outside of Wappler’s Docker-Machine), something that would carry the following arguments:

knex --migrations-directory .wappler/migrations/db --migrations-table-name wappler_migrations --client pg --connection 'postgres://db_user:db_password@docker:9906/db-name' migrate:status

Related to: