I am trying to be a little more specific:
Login to your server (See here for an AMI an here for a VM). Run the following (/opt/bitnami represents the installation directory for an AMI or a VM, for a native installer you should replace it with the path you have used):
git checkout Gemfile*
bundle install --without development test sqlite --binstubs --deployment
ruby bin/rake db:migrate RAILS_ENV=production
ruby bin/rake assets:precompile RAILS_ENV=production
/opt/bitnami/ctlscript.sh restart apache
If you find any issue let us know.
I hope it helps.