The Archetype uses the DoctrineMigrationsBundle for the database migrations.
When a new entity is added or modified a new migration can be created from the command line:
console doctrine:migrations:diff
This command will create a new class in the src/Migrations folder which you can use to run your migration back and forth.
To update your database to the latest available version use the command:
console doctrine:migrations:migrate
To undo the last migration run:
console doctrine:migrations:migrate prev
To update your database to the next migration:
console doctrine:migrations:migrate next
You can also migrate to an specific version:
console doctrine:migrations:migrate <timestamp>
Where is the version timestamp. ex: 20100621140655