* activation by email: the user receives an email containing a link to active his account
* manual activation: an email is sent to administrators for account approval (default)
* automatic activation: the user can log in as soon as he has registered

git-svn-id: http://redmine.rubyforge.org/svn/trunk@915 e93f8b46-1217-0410-a6f0-8f06a7374b81