Fix missing type for --days option

feedbackloop/main.py

@@ -38,7 +38,7 @@ def ingest(unseen, limit):
         db.session.commit()
 
 
-@manager.option('--days', default=30)
+@manager.option('--days', type=int, default=30)
 def expire(days):
     """Expire old entries from the database."""
     cutoff = datetime.now() - timedelta(days)