title: Joomla 2.5: assign user to usergroup from front-end
body: <p>I have statically defined user groups with statically defined access rights.
  And I want to be able to change the user group for given user from the front-end using some module.</p>
  
  <p>Reason: users can register by themselves, and automatically go to group "registered". After some time they can be promoted and moved to group "member". But I don't want to do this from back-end, bcs e.g. promotion can be done by any another already member. So I need this in front-end.</p>
  
  <p>I haven't found any mention about this in Google. Maybe this is just something obvious? Are there any module/plugin perfoming such task?</p>