create interface uow update services to uow

src/core/db_manager.py

@@ -0,0 +1,18 @@
+from src.repository.users import UsersRepo
+
+
+class DBManager:
+    def __init__(self, session_factory):
+        self.session_factory = session_factory
+
+    async def __aenter__(self):
+        self.session = self.session_factory()
+        self.user = UsersRepo(self.session)
+        return self
+
+    async def __aexit__(self, exc_type, exc_val, exc_tb):
+        await self.session.rollback()
+        await self.session.close()
+
+    async def commit(self):
+        await self.session.commit()