npm 'missing script payload'

Kia ora!

I'm running payload via the Astroad docker containers, and am struggling to get migrations working.

I initially had a unique 'slug' field in some collections I realised I didn't need, so I removed it from my payload config. I'm running into issues (getting the 'slug not unique' error) so I assume MongoDB is unhappy because it's still expecting a unique slug. I want to run a migration to remove this field totally.

However, after adding the 'payload' script to package.json, trying to run 'npm run payload migrate' gives me a 'missing script: "payload"' error.

I'm running payload 2.1