Symfony - How to logout a user

# vim app/config/security.yml

# app/config/security.yml
security:
    firewalls:
        main:
            logout:
                path:   /logout
                target: /
                invalidate_session: false

Reference:

http://symfony.com/doc/current/reference/configuration/security.html
http://stackoverflow.com/questions/11043672/symfony-logout-handler