Create subdomain on Koding.com http://learn.koding.com/koding-subdomains-and-vhosts/

koding_create_subdomain.sh

#subdomain name
echo -n "Name of your subdomain ?"
read -e subdomain

if [[ $subdomain != "" ]]
  then 
    mkdir ~/$subdomain
    sudo touch /etc/apache2/sites-available/$subdomain
    sudo echo "<Virtualhost *:80>" >> /etc/apache2/sites-available/$subdomain
    sudo echo " ServerName $subdomain.username.kd.io" >> /etc/apache2/sites-available/$subdomain
    sudo echo " DocumentRoot ~/$subdomain" >> /etc/apache2/sites-available/$subdomain
    sudo echo "</Virtualhost>" >> /etc/apache2/sites-available/$subdomain
    sudo a2ensite $subdomain
    sudo service apache2 reload
fi

echo "Done! Now go to your profil and add the new subdomain!"

Is the username dynamic?