this keyboard layout is based on a Apple US ANSI keyboard layout with the following changes
option + a->äoption + o->öoption + u->üoption + e->€option + shift + a->Äoption + shift + u->Üoption + shift + o->Öoption + shift + s->ẞ
copy bundle into ~/Library/Keyboard\ Layouts/ or /Library/Keyboard\ Layouts/