Docker gogs and custom folder not working

Using docker gogs 0.13.0+dev

My custom/conf/app.ini has TLS info:
CERT_FILE = custom/https/cert.pem
KEY_FILE = custom/https/cert.key

Kept getting errors:
2021/02/05 17:35:01 [ INFO] Gogs 0.13.0+dev
2021/02/05 17:35:01 [ INFO] Run mode: Production
2021/02/05 17:35:02 [ INFO] Listen on https ://0.0.0.0:3000
2021/02/05 17:35:02 [FATAL] [gogs.io/gogs/internal/cmd/web.go:769 runWeb()] Failed to start server: open custom/https/cert.pem: no such file or directory

When I was explicit about where it was:
CERT_FILE = /data/gogs/https/cert.pem
KEY_FILE = /data/gogs/https/cert.key

it ran just fine:
2021/02/05 17:35:02 [ INFO] Gogs 0.13.0+dev
2021/02/05 17:35:03 [ INFO] Run mode: Production
2021/02/05 17:35:03 [ INFO] Listen on https ://0.0.0.0:3000

FYI I wasn’t able to find templates/.VERSION