feat: database migration

pkg/persistence/migration.py

@@ -0,0 +1,38 @@
+from __future__ import annotations
+
+import typing
+import abc
+
+from ..core import app
+
+
+preregistered_db_migrations: list[typing.Type[DBMigration]] = []
+
+def migration_class(number: int):
+    """迁移类装饰器"""
+
+    def wrapper(cls: typing.Type[DBMigration]) -> typing.Type[DBMigration]:
+        cls.number = number
+        preregistered_db_migrations.append(cls)
+        return cls
+    return wrapper
+
+
+class DBMigration(abc.ABC):
+    """数据库迁移"""
+
+    number: int
+    """迁移号"""
+
+    def __init__(self, ap: app.Application):
+        self.ap = ap
+
+    @abc.abstractmethod
+    async def upgrade(self):
+        """升级"""
+        pass
+
+    @abc.abstractmethod
+    async def downgrade(self):
+        """降级"""
+        pass