fail

And then it all made sense. The app uses band slugs (like "led-zeppelin") for ids, so the band_id was a string. In ruby, 'string'.to_i is 0, which is why all songs had a band_id of 0, and they didn't show up for any of the bands.

I learned about the idea of being a señor engineer and publishing your fails during your work from Kenneth Larsen [https://www.kennethlarsen.org/] a few years ago. I really liked the idea