title: button= appended as last param in elasticsearch search form
body: <p>I'm using elasticsearch and have run into a weird issue. I have a form for users to submit their search but for some reason, when a user enters their query and then clicks on the submit button, the last parameter is button=
  See bellow:</p>
  
  <p><a href="http://lvh.me:3000/products?utf8=(checkmark)&amp;q=tree&amp;button=" rel="nofollow">http://lvh.me:3000/products?utf8=(checkmark)&amp;q=tree&amp;button=</a></p>
  
  <p>Here is the form. Not sure if this is an issue with the form, rails, or elastic search.</p>
  
  <pre><code>section.search
        = form_tag main_app.products_path, method: :get
          = text_field_tag 'q', nil, placeholder: t(:search)
          = button_tag type: 'submit'
            = icon('fa fa-search')
  </code></pre>
  
  <p>(edit) HTML:</p>
  
  <pre><code>&lt;form action="/products" accept-charset="UTF-8" method="get"&gt;&lt;input name="utf8" type="hidden" value="✓"&gt;
                  &lt;input type="text" name="q" id="q" placeholder="Search"&gt;&lt;button name="button" type="submit"&gt;
  </code></pre>
  
  <p></p>
  
  <p>Any help appreciated! </p>