My first 5 minutes on an Ubuntu server

passwd root
apt-get install lsb-release
echo deb http://archive.ubuntu.com/ubuntu $(lsb_release -cs) main universe > /etc/apt/sources.list.d/universe.list
apt-get update
apt-get install docker.io
ln -sf /usr/bin/docker.io /usr/local/bin/docker
useradd -G sudo -s /bin/bash -m developer
passwd developer
mkdir /home/developer/.ssh
touch /home/developer/.ssh/authorized_keys
chmod 700 /home/developer/.ssh
chmod 400 /home/developer/.ssh/authorized_keys
chown -R developer:developer /home/developer
# copy public key to /home/developer/.ssh/authorized_keys
# edit /etc/ssh/sshd_config
#   PermitRootLogin no
#   PasswordAuthentication no
#   AllowUsers developer
service ssh restart
# test the ssh config by connecting from a different shell
exit