Handling migrations in EE,
Migration Classes & file structure
Migrations will be used to make changes(db/file/containers) to existing ee installation.
Migrations will be stored in
/migrations folder in EE root.
Each migration will be stored in seperate file. Name would be like 'timestamp_migration_title.php' i.e '1530101102_migrate_to_beta2.php'
Each of them will have a class that will extend a base abstract class. The abstract class will have one method - migrate(). The class that implements it can create more methods to group different types of changes.