Requires models that are to be migrated to be provided before init.
Assumes models use GORM, currently. Future enhancements will guarantee that GORM models will work for non-GORM-supported SQL DBs (if that's a thing).
Will pull DB connection info and credentials from SQL_URL. If not found, it will try DATABASE_URL, then DB_URL.
If any part of the needed credentials are not obtained at that stage, it will use:
DB_DIALECT
DB_USER
DB_PASSWORD
DB_DBNAME
At present, the dialects available are limited to postgres, sqlite3. If none is detected,
sqlite3 will be used (in memory). For example, you could use sqlite3 to connect to a file with SQL_URL=sqlite3:///tmp/test.db
or something like postgres://test:test@localhost:5432/test or postgres://test:test@localhost:5432/test?sslmode=disable to connect via postgres.