Heroku inspecciona babosas y enumera gemas

How I can inspect the my Heroku app's slug? I'd like to see which versions of which gems it has installed. I know when the slug compiles it lists which gems it installs, but I want to see what gems my app is using ahora (if it recompiles the gems differ, I am investigating a bug)

This is all the information I could find about my app, the gems aren't listed :(

$ heroku apps:info
=== placeboxy
Addons:        cron:daily
               pusher:sandbox
               shared-database:5mb

Database Size: 112k
Dynos:         1
Git URL:       
Owner Email:   
Repo Size:     1M
Slug Size:     6M
Stack:         bamboo-ree-1.8.7
Web URL:       
Workers:       0