How to create a new migration
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1. Go to contessa dir
2. Run `alembic revision -m "<name_of_the_migration>"`
3. It will generate script for iterating all the quality tables by each quality model.
   E.g. QualityCheck and ConsistencyCheck models.
4. Code your migration for models you have changed.
5. Write integration tests. (use `MigrationTestCase`)
6. Profit
