title: select_tag doesn't save the selected option
body: <p>I'm new in web development &amp; Rails. I've been struggling to understand why my form is not getting saved completely. Here is the code I'm using:</p>
  
  <pre><code>  &lt;div class="field"&gt;
      &lt;%= f.label :type %&gt;&lt;br&gt;
      &lt;%= select_tag(:type, options_for_select([['Verb', 'Verb'], ['Adjective', 'Adjective'], ['Noun','Noun'],['Preposition','Preposition'],['Article','Article'],['Adverb','Adverb']])) %&gt;
    &lt;/div&gt;
    &lt;div class="field"&gt;
      &lt;%= f.label :category %&gt;&lt;br&gt;
      &lt;%= select_tag "category",
                     "&lt;option&gt;Appliances&lt;/option&gt;
                      &lt;option&gt;Clothes and Accessories&lt;/option&gt;
                      &lt;option&gt;Colours&lt;/option&gt;
                      &lt;option&gt;Communication and Technology&lt;/option&gt;
                      &lt;option&gt;Documents and Texts&lt;/option&gt;
                      &lt;option&gt;Education&lt;/option&gt;
                      &lt;option&gt;Entertainment and Media&lt;/option&gt;
                      &lt;option&gt;Family and Friends&lt;/option&gt;
                      &lt;option&gt;Food and Drink&lt;/option&gt;
                      &lt;option&gt;Health, Medicine and Exercise&lt;/option&gt;
                      &lt;option&gt;Hobbies and Leisure&lt;/option&gt;
                      &lt;option&gt;House and Home&lt;/option&gt;
                      &lt;option&gt;Measurements&lt;/option&gt;
                      &lt;option&gt;Personal Feelings, Opinions and Experiences (adjectives)&lt;/option&gt;
                      &lt;option&gt;Places: Buildings&lt;/option&gt;
                      &lt;option&gt;Places: Countryside&lt;/option&gt;
                      &lt;option&gt;Places: Town and City&lt;/option&gt;
                      &lt;option&gt;Services&lt;/option&gt;
                      &lt;option&gt;Shopping&lt;/option&gt;
                      &lt;option&gt;Sport&lt;/option&gt;
                      &lt;option&gt;The Natural World&lt;/option&gt;
                      &lt;option&gt;Time&lt;/option&gt;
                      &lt;option&gt;Travel and Transport&lt;/option&gt;
                      &lt;option&gt;Weather&lt;/option&gt;
                      &lt;option&gt;Work and Jobs&lt;/option&gt;".html_safe %&gt;
    &lt;/div&gt;
  </code></pre>
  
  <p>PS: I've kept two different methods I tried to use.</p>