[phases.setup]
aptPkgs = ["ffmpeg"] 

Pasted above is my entire backend/nixpacks.toml (I have a monorepo with frontend and backend directories). My general build and deploy instructions are immature but not sure why this doesn't work?

Here's the railway.toml from the frontend Railway provides.

[build]
builder = "NIXPACKS"
buildCommand = "cd backend && make build"
nixpacksPlan = {"providers":["go"]}

[deploy]
runtime = "V2"
numReplicas = 1
startCommand = "cd backend && ./backend"
sleepApplication = false
multiRegionConfig = {"us-west2":{"numReplicas":1}}
restartPolicyType = "ON_FAILURE"
restartPolicyMaxRetries = 10

When I run the final code, during the process where it uses ffmpeg, it fails with
5:40AM ERR FFmpeg command failed error="exec: \"ffmpeg\": executable file not found in $PATH"