ruby-on-rails – Rails 5：验证复选框的接受程度

我正在尝试验证何时选中复选框,如果没有则返回错误.

validates_acceptance_of :agreement,:allow_nil => true,:accept => true,:on => :create

我有一个布尔列,在accounts表中设置为默认值.

add_column :accounts,:agreement,:boolean,default: false

此外,我已将：协议添加到允许的控制器参数中.

这是形式：

<%= form_for(resource,as: resource_name,url: registration_path(resource_name)) do |f| %>
    <div class="centerList">
      <div id="error_explanation">
        <%= devise_error_messages! %></div>
    </div>

      <div class="form-group">
        <span class="asterisk_input"></span>
        <%= f.email_field :email,autofocus: true,placeholder: "email",:class=>"form-control" %>
      </div>

      <div class="form-group">
        <span class="asterisk_input"></span>
        <%= f.password_field :password,placeholder: "password",autocomplete: "off",:class=>"form-control" %>
      </div>

      <div class="form-group">
        <span class="asterisk_input"></span>
        <%= f.password_field :password_confirmation,placeholder: "confirm password",:class=>"form-control"  %>
      </div>

      <%= f.fields_for :account do |form| %>


      <div class="form-group">
        <span class="asterisk_input"></span>
        <%= form.text_field :street,placeholder: "street",:class=>"form-control" %>
      </div>

      <div class="form-group">
        <span class="asterisk_input"></span>
        <%= form.text_field :city,placeholder: "city",:class=>"form-control"  %>
      </div>

      <div class="form-group">
        <span class="asterisk_input"></span>
        <%= form.text_field :state,placeholder: "state",:class=>"form-control" %>
      </div>

      <div class="form-group">
        <span class="asterisk_input"></span>
        <%= form.text_field :zip_code,placeholder: "zip code",:class=>"form-control" %>
      </div>

      <div class="form-group">
        <span class="asterisk_input"></span>
        <%= form.country_select :country,["US"],{},{ :class => "form-control",:id=>"sign-frm-input" } %>
      </div>

      <div class="form-group">
          <%= form.check_box :agreement %> I agree to the <%= link_to 'Terms',term_path(:id=>1) %>.
      </div>

<% end %>
      <div class="form-group">
        <%= f.submit "Sign up",:class=>'btn btn-primary' %>
  <% end %>

但它返回表格错误协议必须被接受,即使我接受它.任何想法我可能会遗漏的东西！