Migrate Command

Hi, i´m new in Yii and my question is:

I´ve installed Yii 2 and created a new app, now i´m trying to run migrate command, i got a database in a mysql server, and when run migrate command, Yii tells me, that already exist the user table, but already got my user table in database.

How can use my user table? or i use the default user table and then extends it ?

if the answer is the second, how i can do this?