failed to get last fit ranking model time

[aqlx86]

Gorse version

Version:	 v0.4.15
API version:	 v0.2.7
Go version:	 go1.20.12
Git commit:	 09ad3aa8cdf4c46408f774668ff2fffa458a34ed
Built:		 Wed Jan 10 04:45:06 UTC 2024
OS/Arch:	 linux/amd64

Describe the bug
I see in logs

{"level":"warn","ts":1721912611.414353,"msg":"failed to get last fit ranking model time","request_id":"fadb4ad1-de67-4ef3-b7c3-2350df763d8b","error":"global_meta/last_fit_ranking_model_time: object not found","errorVerbose":"github.com/zhenghaoz/gorse/storage/cache.init:132: object not found\ngit.luolix.top/zhenghaoz/gorse/storage/cache.(*Redis).Get:299: global_meta/last_fit_ranking_model_time"}

To Reproduce

• use redis for cache
• use postgres for database
• prefix set to gorse_

the rest is same in config