Unrootify yourself in a newly created ubuntu instance

unrootify_ubuntu

export USERNAME=yigit
echo -e "\n\nAllowUsers root $USERNAME" >> /etc/ssh/sshd_config
sudo service ssh restart
mkdir -p /home/$USERNAME/.ssh
cp /root/.ssh/authorized_keys /home/$USERNAME/.ssh
sudo adduser $USERNAME
sudo adduser $USERNAME sudo
sudo chown -R $USERNAME /home/$USERNAME

# To make this user a ssh user
sudo chown -R $USERNAME:$USERNAME /home/$USERNAME/.ssh
sudo chmod 0700 /home/$USERNAME/.ssh
sudo chmod 0600 /home/$USERNAME/.ssh/authorized_keys
service ssh reload

# To add user to sudoers
usermod -aG sudo $USERNAME