How to see 500 errors debug in production in Amber Framework?

I followed the amber framework guides to get a simple app up and running. Locally, it runs fine.

On prod heroku however, I just HTTP 500 errors and in config/ I set

settings.logging.severity = "debug"

The home page works fine, the Welcome to Amber Framework! message.

But when I hit my endpoints I see:

2019-02-04T23:42:01.223860+00:00 heroku[router]: at=info method=GET path="/api/v1/games" request_id=08991879-897c-4aaf-bec0-fe5f0ce2285a fwd="" dyno=web.1 connect=0ms service=233ms status=500 bytes=91461 protocol=http
2019-02-04T23:42:01.361031+00:00 heroku[router]: at=info method=GET path="/client-reload" request_id=ff573e6d-84b3-4b17-9fc7-6ed0602d3e2f fwd="" dyno=web.1 connect=0ms service=11488ms status=101 bytes=129 protocol=http
2019-02-04T23:42:03.221075+00:00 heroku[router]: at=info method=GET path="/api/v1/games" request_id=f50151b0-2eca-46a5-a739-12247164abe4 fwd="" dyno=web.1 connect=0ms service=11ms status=500 bytes=91461 protocol=http
2019-02-04T23:42:03.214144+00:00 app[web.1]: 11:42:03 Error: 500 | (ERROR)
2019-02-04T23:42:03.328016+00:00 heroku[router]: at=info method=GET path="/favicon.ico" request_id=c598686c-ab75-494e-aadc-9eb003b63d95 fwd="" dyno=web.1 connect=0ms service=3ms status=200 bytes=15266 protocol=http
2019-02-04T23:42:05.424545+00:00 heroku[router]: at=info method=GET path="/favicon.ico" request_id=15cb9ed8-1ed4-442e-afb7-d0cefb7db332 fwd="" dyno=web.1 connect=0ms service=1ms status=200 bytes=15266 protocol=http
2019-02-04T23:42:05.325568+00:00 heroku[router]: at=info method=GET path="/api/v1/games" request_id=b3f5b695-2425-4b8b-92d5-2d3097e83a96 fwd="" dyno=web.1 connect=0ms service=12ms status=500 bytes=91461 protocol=http
2019-02-04T23:42:05.317633+00:00 app[web.1]: 11:42:05 Error: 500 | (ERROR)

At first I thought it was a database url error, but I have managed to run my migrations properly.

At this point I just want to see more info related to the 500. How can I do that?