Same issue on a fresh Ubuntu 14.04 install.
When trying to apply @jessp01 suggestions, the following happens:
# ./launcher start app
+ /usr/bin/docker run -d --restart=always -e LANG=en_US.UTF-8 -e RAILS_ENV=production -e UNICORN_WORKERS=3 -e UNICORN_SIDEKIQS=1 -e RUBY_GC_MALLOC_LIMIT=40000000 -e RUBY_HEAP_MIN_SLOTS=800000 -e DISCOURSE_DB_SOCKET=/var/run/postgresql -e DISCOURSE_DB_HOST= -e DISCOURSE_DB_PORT= -e HOME=/root -e DISCOURSE_DEVELOPER_EMAILS=jivan.roquet@uptilab.com -e DISCOURSE_HOSTNAME=discuss.uptilab.com -e DISCOURSE_SMTP_ADDRESS=smtp.mandrillapp.com -e DISCOURSE_SMTP_PORT=587 -e DISCOURSE_SMTP_USER_NAME=jivan.roquet@uptilab.com -e DISCOURSE_SMTP_PASSWORD=Nufe6_2f9LsorzwLNP5v2g -h jeff-app -e DOCKER_HOST_IP=172.17.42.1 --name app -t -p 80:80 -p 2222:22 -v /var/discourse/shared/standalone:/shared -v /var/discourse/shared/standalone/log/var-log:/var/log local_discourse/app /sbin/boot
Unable to find image 'local_discourse/app:latest' locally
Pulling repository docker.io/local_discourse/app
Error: image local_discourse/app:latest not found
# ./launcher enter app
Error response from daemon: no such id: app
cd /var/www/discourse && su discourse -c 'bundle install --deployment --verbose --without test --without development'
bash: cd: /var/www/discourse: No such file or directory