[TYPO3-mvc] addUsergroup in extended feUser

[Domi]

Hey Lorenz,

yeah, I get an object of Tx_Extbase_Domain_Model_FrondendUserGroup, so 
everything should work, from what I see in the debugger. Do I need any 
kind of additional TS setup, for now I just used the extension_builder, 
which extended my class Client with extbase FrondendUser. All my domain 
actions work as expected, I can set password and username without problems.

Why does it end up in a white website, without error message in TYPO3 
los, neither in my apache log.

Thanks for any help,

Cheers Dominic