How to change the email credentials

I have read the basic documentation in Laravel 5.0 for sending email using my gmail account, this is fine for testing but, how do I setup the credentials

username and password according to each user, I mean this cannot be static on config/email.php:

'username' => 'useremail@gmail.com',
'password' => 'password',

or I'm mistaken? or what is the correct way to deal with this? Thanks

via Chebli Mohamed