Using proper language navigating

app/views/layouts/application.html.slim

@@ -1,4 +1,4 @@
-html
+html lang="#{I18n.locale}"
   head
     title #CH420 - #{content_for(:title)}
     = stylesheet_link_tag    'application', media: 'all', 'data-turbolinks-track' => true

app/views/supporters/_form.slim

@@ -5,14 +5,15 @@
     h1
       = title t('.title_html')
   .col-xs-12.col-md-3
-    .pull-right
-      a href='/' 
+    nav.pull-right
+      h2.sr-only =t('.lang')
+      a href='/' lang='de'
         | Deutsch
       |   |  
-      a href='/it' 
+      a href='/it' lang='it'
         | Italiano
       |   |  
-      a href='/fr' 
+      a href='/fr' lang='fr'
         | Français
     br/
     = render 'shared/counter'