How to add user and grant Root Privileges in centos 7

Description: To assign root privileges to another user on centos 7

Procedure: 

• First add user using below command 

# adduser testuser1

• Set password to user 

# passwd testuser1

• Grant privileges to user using below command 

# visudo

## find the following content
root ALL=(ALL) ALL
## Add following content
testuser1 ALL=(ALL) ALL

• Then save and exit file using :wq command
• To test privileges login with testuser1 and use below command to take previleges

$ sudo su
password prompt for testuser1 now testuser1 can run all commands as a root.