ruby - Rails中的命名空间表单对象

我很难在我正在构建的新的Rails 6项目中设置一些自定义表单对象。我怀疑这可能是由于命名空间问题引起的，但我还不能确定。

app / views / saasy / signups / new.html.erb

<%= form_with(model: [ :saasy, @signup ], url: saasy_signups_path(@signup),  local: true) do |signup_form| %>

  <%= fields_for :account, @signup.account do |account_fields| %>
    Organization name: <%= account_fields.text_field :organization %>
  <% end %>

  <%= signup_form.submit %>
<% end %>

应用程序/控制器/saasy/signups_controller.rb

class Saasy::SignupsController < ApplicationController
  def new
    @signup = Saasy::SignupForm.new
  end

  def create
    @signup = Saasy::SignupForm.new(signup_form_params)
    @signup.register
  end

  private

  def signup_form_params
    params
      .require(:saasy_signup_form)
      .permit(account_attributes: [:organization])
  end
end

config / routes.rb

Rails.application.routes.draw do
  namespace :saasy do
    resources :signups, only: [:new, :create]
  end
end

app / forms / saasy / signup_form.rb

module Saasy
  class SignupForm
    include ActiveModel::Model

    attr_accessor :user, :account

    delegate :attributes=, to: :user, prefix: true
    delegate :attributes=, to: :account, prefix: true

    def initialize(params= {})
      super(params)
      @user = Saasy::User.new(params)
      @account = Saasy::Account.new(params)
    end

    def register
      # eventually do actual signup stuff here
    end

  end
end

但是，无论何时进行测试，我都会收到以下消息：参数丢失或值为空：signup_form

params哈希看起来像这样：

{
"authenticity_token"=>"BhhvRaYKf220afExocQ//LIY1jszVsXs+lThFeUFKvr6ciVBsa+22mSxwO3yT6mK2uOsWSCKx9gL6WIaGmmvSg==", 
"account"=>{"organization"=>"Example Name"}, 
"commit"=>"Create Signup form"
}

我已经尝试了很多解决方案，例如form_with在视图中玩和更改路线名称等，但是到目前为止我还没有运气。任何建议将不胜感激！