grant root permission to user ubuntu code example

Example 1: grant superuser permission to sudo user ubuntu

adduser sudo_user_name
//grant privileges
visudo
under line 
root ALL=(ALL:ALL) ALL 
add this line
sudo_user_name ALL=(ALL:ALL) ALL
sudo apt-get update

Example 2: grant all the permission to the user ubuntu

The simplest way is to use chown:

sudo chown -R testuser:testuser /var/www/test/public_html