title: rails, slim and form_tag does not allow more then one on a page
body: <p>I am using slim templates for my rails application. But something strang is happening. In my application template I have a form like so:</p>
  
  <pre><code>= form_tag search_path, class:'navbar-search pull-left', remote: true
  = text_field_tag :term, nil, class: 'search-query span2', placeholder: 'Search'
  </code></pre>
  
  <p>That renders well on my page and the search form is working fine. However in my sign up partial I have:</p>
  
  <pre><code>= form_tag '/auth/identity/callback'
          - if @identity &amp;&amp; @identity.errors.any?
          div.error
              h2 =pluralize(@identity.errors.count, 'error')
              |prohibited this account from being saved:
              ul
                  - @identity.errors.full_messages.each do |msg|
                      li =msg
      h1
          i.iconbig-lock
          | Sign In
      div.login-fields
          p Sign In using your email:
          div.field
              = label_tag :auth_key, 'Email'
              = text_field_tag :auth_key, nil, class: 'input login username-field', placeholder: 'Email'
          div.field
              = label_tag :password, 'Password'
              = password_field_tag :password, nil, class:'login password-field', placeholder: 'password'
          div.login-actions
              = submit_tag 'Login', class: 'btn-signin btn btn-primary'
          div.login-social.marg10-btm
              p Sign in using social network:
              a.btn
                  = image_tag 'twitter-18.png'
                  |  Signin with twitter
              a.btn href="/auth/facebook"
                  = image_tag 'facebook-18.png'
                  |  Signin with Facebook
  </code></pre>
  
  <p>the form tag doesn't render, but all sub elements text fields (including the 'authenticity_token') renders fine.</p>
  
  <p>I play around abit and notice that the page only allow 1 form_tag. Ones created after the first never renders. I been looking on google for a while and could not figure why. Any ideas? </p>