Thanks mate, I uncommented this line and I’ve just rebuilt the app, however http://specknz.me/ is still not working 
Removing old container
+ /usr/bin/docker rm app
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_GLOBAL_METHOD_CACHE_SIZE=131072 -e DISCOURSE_DB_SOCKET=/var/run/postgresql -e DISCOURSE_DB_HOST= -e DISCOURSE_DB_PORT= -e LETSENCRYPT_DIR=/shared/letsencrypt -e LETSENCRYPT_ACCOUNT_EMAIL=********@gmail.com -e DISCOURSE_HOSTNAME=speckme.nz -e DISCOURSE_DEVELOPER_EMAILS=********@gmail.com -e DISCOURSE_SMTP_ADDRESS=smtp.gmail.com -h discourse-app -e DOCKER_HOST_IP=172.17.0.1 --name app -t -p 80:80 -p 443:443 -v /var/discourse/shared/standalone:/shared -v /var/discourse/shared/standalone/log/var-log:/var/log --mac-address 02:f9:8c:dd:3d:63 local_discourse/app /sbin/boot
8196afcbe767c649b3cb20dcb76c607d5267e3e8eaff323f98050de085769137
root@discourse:/var/discourse#