Problem scenario
You modified the /etc/sudoers file. The changes do not seem to have taken effect. What should you do?
Solution
99% of the time you do not need to log out or log back in. You should not need to open another terminal. For the stanza that you added, did you append it to the bottom? The problem may be that the stanza you added was in the middle of the file. If you are new to editing the /etc/sudoers file, try putting the stanza at the bottom. The changes should take effect instantaneously.