Same thing happened
Output
Webpacker is installed 🎉 🍰
Using /app/config/webpacker.yml file for setting up webpack paths
[Webpacker] Compiling assets 🎉
[Webpacker] Compilation Failed
/usr/bin/env: ‘ruby\r’: No such file or directory
Error : failed to execute hook (compile) on 71e1ed7c254ca320b38a42aca4dc394df082bc32c0dfe70b06ed711126dec30d: util:Exec:/opt/nanobox/hooks/compile: bad exit code(1):
Context : failed to build the code