change warn to use rails logger

[yule]

This allows backtrace_silencers to be able to ignore this error. It also behaves nicely on what is set as log level in the environment file.

Prior to this, having config.log_level = :fatal will still output this warning as it uses the kernel warn rather than the rails logging facility.

Given that refinery is designed to run in rails, this will be the case in all cases.

[yule]

will add test....

[parndt]

Thank you! Great work! 👍

I've merged your work to 572fff8 and also made it possible to inject the logger, defaulting to the Rails logger in 46b5066