API - Collections in Ruby

Hi - I'm working on an API call with a new developer and she is not familiar with Ruby like the last developer was. We are just tweaking something so it doesn't need to be a huge new build, but we are running into an issue when trying to update a collection.

Specifically, we are trying to update the Resource Pools on a user.

We have tried some of the things mentioned on the API documentation about nested objects, but we can't get it to work. If anyone knows Ruby and has worked on something like this, let me know. :)