title: How to add id into options_for_select on select_tag rails
body: <p>I'm trying to implements <code>select_tag</code> on rails. And I wish to add select option on each option value with id. This is my select_tag code :</p>
  
  <pre><code>&lt;%= select_tag "type", options_for_select(@form_type, :selected =&gt; form.values.first.form_type._id, id: "#{form.values.first.form_type.key}"), name: "core_template[form][#{index.to_s}][type]", class: "form-control change-type", id:"core_template_type#{index.to_s}", :prompt =&gt; "Select Type", :required=&gt;"required" %&gt;
  </code></pre>
  
  <p>and the select_tag generate html like below :</p>
  
  <pre><code>&lt;select name="core_template[form][0][type]" id="core_template_type0" class="form-control change-type" required="required"&gt;&lt;option value=""&gt;Select Type&lt;/option&gt;&lt;option selected="selected" value="57562dbba3399025ca000001"&gt;Check Box&lt;/option&gt;
  &lt;option value="57562ddaa3399025ca000003"&gt;Free Text&lt;/option&gt;
  &lt;option value="57562dcda3399025ca000002"&gt;Radio Button&lt;/option&gt;
  &lt;option value="57578fc6a339900db7000002"&gt;Text Area&lt;/option&gt;&lt;/select&gt;
  </code></pre>
  
  <p>I want to add id to each option value like below :</p>
  
  <pre><code>&lt;select name="core_template[form][0][type]" id="core_template_type0" class="form-control change-type" required="required"&gt;&lt;option value=""&gt;Select Type&lt;/option&gt;&lt;option selected="selected" value="57562dbba3399025ca000001"&gt;Check Box&lt;/option&gt;
  &lt;option value="57562ddaa3399025ca000003" id="free_text"&gt;Free Text&lt;/option&gt;
  &lt;option value="57562dcda3399025ca000002" id="radio_button"&gt;Radio Button&lt;/option&gt;
  &lt;option value="57578fc6a339900db7000002" id="text_area"&gt;Text Area&lt;/option&gt;&lt;/select&gt;
  </code></pre>
  
  <p>how to do that?
  thank you master</p>