give sudo permission to docker code example

Example 1: make docker sudo less

$ sudo groupadd docker
$ sudo usermod -aG docker $USER
$ newgrp docker

Example 2: docker post installation steps linux

# Creates docker group
sudo groupadd docker

# Add your user to the docker group
sudo usermod -aG docker $USER

# Log out and log back in so that your group membership is re-evaluated
# GNOME example
gnome-session-quit