mysql --user=root mysql -p

Insert your MySQL root password, it will jump you to mysql database (keeping user account information);

mysql> GRANT ALL PRIVILEGES ON *.* TO 'username'@'localhost'
->     IDENTIFIED BY 'some_pass' WITH GRANT OPTION;
mysql> GRANT ALL PRIVILEGES ON *.* TO 'username'@'%'
->     IDENTIFIED BY 'some_pass' WITH GRANT OPTION;

This is when you want the spesific user to have all access to all database from anywhere (username@%)