Using Command Line how to make the user an Administrator

As soon I bind a Mac to the AD Domain, I usually log into the Mac with the user account. Of course, under System Preference, User & Groups, the user account is marked as: Managed, Mobile My second step, is to make the user an Administrator account because I want to allow him/her to install/remove stuff from her/his Mac. So, with the GUI, System Preferences > Users & Groups > I select the user name and I check mark the option: enable Allow user to administer this computer and I restart the machine and everything works fine. The user now is an Admin for that machine. Question, how do I perform the above process with the command line in Terminal? Not the bind process, but to make the user Admin for that specific machine.