title: active admin has_one duplication inside the select form
body: <p>The input of my active admin code gives me selection of all the addresses duplicated
  I want the addresses without any duplication inside the select form <a href="https://i.stack.imgur.com/nOAy1.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/nOAy1.png" alt="enter image description here" /></a></p>
  <p>in case new</p>
  <pre><code>  &lt;%= form_for @case,:url =&gt; {:action =&gt; :create, :id =&gt; @user.id} do |f| %&gt;
      Address:&lt;br&gt;
      &lt;%= f.select :address, options_for_select(@user.addresses.all.pluck(:name,:id), @case.address&amp;.id) %&gt;&lt;br&gt;&lt;br&gt;&lt;br&gt;
        Patient First Name:&lt;%= f.text_field :pt_first_name, class: &quot;textbox&quot; ,required: &quot;required&quot; ,placeholder: &quot;Patient Name&quot;%&gt;
        Patient Last Name:&lt;%= f.text_field :pt_last_name, class: &quot;textbox&quot; ,required: &quot;required&quot; ,placeholder: &quot;Patient Name&quot;%&gt;
  &lt;% end %&gt;
  </code></pre>
  <p>in active admin case.rb</p>
  <pre><code>ActiveAdmin.register Case do
  permit_params  :user_id, :product_ids,:step_ids  , :pt_first_name,:pt_last_name, 
  :date_received, :due_date, :shade, :mould, :upper_lower,:invoice,:implant_brand, :implant_quantity,address_attributes: [ :name]
  
      form do |f|
              f.inputs do
                  f.input :user
                  f.inputs &quot;address&quot;, for: [:address, f.object.address || Address.new] do |meta_form|
                  meta_form.input :name, :as =&gt; :select, :collection =&gt; Address.order(name: :desc).collect {|address| [address.name, address.id] }
              end
               
              f.input :pt_first_name
              f.input :pt_last_name
  </code></pre>