Log in to MySQL:
mysql -u root
Now create and grant
GRANT ALL PRIVILEGES ON dbTest.* To 'user'@'hostname' IDENTIFIED BY 'password';
Alternately, if you just want to grant full unrestricted access to a database (e.g. on your local machine for a test instance, you can grant access to the anonymous user, like so:
GRANT ALL PRIVILEGES ON dbTest.* To ''@'hostname'
This is fine for junk data in development. Don't do this with anything you care about.