Practical procedure and troubleshooting notes for Add a User to a Group in Ubuntu.

1. Launch your terminal
2. Inside of the terminal you can check what groups the user is already in using the groups command

groups user

4. Once you have verified that the user is not already in the group you wish to add them in you can use the usermod command

man usermod

5. The above command shows all of the available options you have with the usermod command
6. If you wanted to add a user to the webdev group and the sudo group

usermode user --append -g webdev,sudo

7. Congradulations you have add a user to the webdev group and sudo group