{
  "name": "Tryit",
  "description": "Localized Docker Setup",
  "image": "heroku/cedar",
  "addons": [
    "heroku-postgresql"
  ]
}

...
herokuPostgresql_1 | LOG:  autovacuum launcher started
web_1              | bash: bundle: command not found

docker-compose build
herokuPostgresql uses an image, skipping
Building worker2...
Step 0 : FROM heroku/cedar
 ---> a439e8b8893d
Successfully built a439e8b8893d
Building worker3...
Step 0 : FROM heroku/cedar
 ---> a439e8b8893d
Successfully built a439e8b8893d
Building worker1...
Step 0 : FROM heroku/cedar
 ---> a439e8b8893d
Successfully built a439e8b8893d
Building shell...
Step 0 : FROM heroku/cedar
 ---> a439e8b8893d
Successfully built a439e8b8893d
Building web...
Step 0 : FROM heroku/cedar
 ---> a439e8b8893d
Successfully built a439e8b8893d

docker-compose run web gem list

*** LOCAL GEMS ***