<ActionController::Parameters {"given_name"=>"Mark", "subdomain"=>"development", "controller"=>"user", "action"=>"create", "user"=>{"given_name"=>"Mark"}} permitted: false>

{"given_name":"Mark"}

user = User.new(params)

#<ActiveModel::ForbiddenAttributesError: ActiveModel::ForbiddenAttributesError>

def create
    @user = User.new(params.require(:user).permit(:given_name))
end