Fix Docker build

[markets]

The Docker build is failing: https://github.com/coopdevs/timeoverflow/actions/workflows/docker_build.yml.

See more info: #777 (comment)

[markets]

@microstudi Could you please help us with that one 🙏🏼? Since we migrated to Rails 7.2, maybe we need to move to RAILS_MASTER_KEY instead of the current SECRET_KEY_BASE + secrets.yml?

[sseerrggii]

I talked with @microstudi and he told me he was very busy and needed a few days to take a look

[Morantron]

Docker build fixed here #799