ORM Strategy for Testing Data

In my company we have a ORM (SQLAlchemy) were all the Columns and Tables are defined. If we need a new Column we add the Column in the ORM Project Repo and Run a Jenkins Deployment which generates the Database as Docker Image and migrates the Production / Dev Instance. For Local Development Developers just fetch the latest Docker Image from our Docker Registry. The problem is the database has only the Scheme but for some Tests (on Acceptance Instance) we need Demo Data, I was wondering what the best approach is to handle the Demo Data. The Demo Data can be fake data, some fixed data (eg test username and password) and some calculated functions (eg date - two weeks).

I was looking for different approaches but I was wondering which tool you use for datamigration? And how do you store the definition of the data? The Scheme can only be touched from certain developers the Test Data should be also adapted from the QA Developers.

Thanks