def user_params
        if params[:user][:password].blank? && action_name == 'update'
          params[:user].delete(:password)
          params[:user].delete(:password_confirmation)
        end
        params.require(:user).permit(
          :username, :gruppen, :sn, :givenname, :displayname, 
          :telephone, :email, :password, :password_confirmation,
          :title, :position, :department, :company
         )
      end
def user_params
        if params[:user][:password].blank? && action_name == 'update'
          params[:user].delete(:password)
          params[:user].delete(:password_confirmation)
        end
        params.require(:user).permit(
          :username, :gruppen, :sn, :givenname, :displayname, 
          :telephone, :email, :password, :password_confirmation,
          :title, :position, :department, :company
         )
      end
Only allow a trusted parameter "white list" through.