Introduce i18n for site navigation

Author: stomar

_config.yml

@@ -109,3 +109,20 @@ credits:
       Puoi contattare il nostro <a href="mailto:webmaster@ruby-lang.org">webmaster</a>
       per domande e commenti riguardanti questo sito.
 
+nav:
+  en:
+    - name: Downloads
+      url:  downloads
+    - name: Documentation
+      url:  documentation
+    - name: Libraries
+      url:  libraries
+    - name: Community
+      url:  community
+    - name: News
+      url:  news
+    - name: Security
+      url:  security
+    - name: About Ruby
+      url:  about
+

_includes/sitelinks.html

@@ -1 +1,8 @@
-<a href="/{{ page.lang }}/downloads/">Downloads</a><span class="separator"> | </span><a href="/{{ page.lang }}/documentation/">Documentation</a><span class="separator"> | </span><a href="/{{ page.lang }}/libraries/">Libraries</a><span class="separator"> | </span><a href="/{{ page.lang }}/community/">Community</a><span class="separator"> | </span><a href="/{{ page.lang }}/news/">News</a><span class="separator"> | </span><a href="/{{ page.lang }}/security/">Security</a><span class="separator"> | </span><a href="/{{ page.lang }}/about/">About Ruby</a>
+{% if site.nav[page.lang] %}
+  {% assign navlang = page.lang %}
+{% else %}
+  {% assign navlang = 'en' %}
+{% endif %}
+{% for link in site.nav[navlang] %}
+  <a href="/{{ page.lang }}/{{ link.url }}/">{{ link.name }}</a>{% unless forloop.last %}<span class="separator"> | </span>{% endunless %}
+{% endfor %}