I'll look into this to see if anything has changed with Importmaps in the past few months. However, the last time I looked, there's a lot of "going against the grain" with importmaps when it comes to javascript libraries that also provide their own CSS. My initial thought is that you would still need to use Yarn to also bring in those libraries so that you can consume the CSS.

I'm glad you were able to figure out a solution, would you mind posting it in case it helps someone else?

Smaller applications, I'm thinking like Campfire, makes sense to go without a dockerized environment. But, at the same time, if you have to context switch a lot between different applications, it can really solve environmental conflicts (different PG versions, imagemagick versions, etc.) Ideally, all of our apps will be on the same version and updated, but that's not always reality.

  john.wallace  Thank you for letting me know. I've updated the ZIP and Code tab with the code. I have no idea how I messed that up, but luckily, I was able to copy and paste all of the code from this example into the previous episode's code and it worked! 

The object that you're calling insert_at is nil. Try logging what the item is to make sure that it is being found. It's currently returning nil, so you should trace upwards to see what the params[:sgid] is being set to. If the params[:sgid] is nil, then you go upwards from there to what's calling the controller and find out why it is nil.