boton de guardar tambien al final

app/views/posts/_form.haml

@@ -110,6 +110,8 @@
       = text_field 'post', "lang[#{lang}]", value: @post.get_front_matter(:lang).dig(lang),
         class: 'form-control'
       %small.text-muted.form-text= t('posts.lang_help')
+  .form-group
+    = submit_tag t('posts.save'), class: 'btn btn-success'
 
 :javascript
   $(document).on('turbolinks:load', function() {