add user with ssh pub key unix

sudo mkdir /home/tomcat8
sudo groupadd tomcat8
sudo useradd -s /bin/sh -g tomcat8 -d /home/tomcat8 tomcat8
usermod -s /bin/sh tomcat8 change user cli
usermod -a -G sudo tomcat8

groups
groups username
chmod 700 -R /home/user
sudo chmod 700 /home/user/.ssh
sudo chmod 600 /home/almas/.ssh/authorized_keys

execute sudo cmd without passwd:
sudo visudo
In the bottom of the file, type the follow:

username ALL=(ALL) NOPASSWD: ALL