feat: 初始提交

backend/app/repositories/usage_metric_repository.py

@@ -0,0 +1,19 @@
+from typing import Optional
+
+from sqlalchemy import select
+
+from .base import BaseRepository
+from ..models import UsageMetric
+
+
+class UsageMetricRepository(BaseRepository[UsageMetric]):
+    model = UsageMetric
+
+    async def get_or_create(self, key: str) -> UsageMetric:
+        result = await self.session.execute(select(UsageMetric).where(UsageMetric.key == key))
+        instance = result.scalars().first()
+        if instance is None:
+            instance = UsageMetric(key=key, value=0)
+            self.session.add(instance)
+            await self.session.flush()
+        return instance