Added tag and category index to index.html.

index.html

@@ -34,12 +34,33 @@ title: Welcome to the Wiki
         <h3>
 <a name="welcome-to-github-pages" class="anchor" href="#welcome-to-github-pages"><span class="octicon octicon-link"></span></a>Welcome to GitHub Pages.</h3>
 
+<p>All posts:</p>
 <ul>
   {% for post in site.posts %}
     <li><a href="{{ post.url }}">{{ post.title }}</a></li>
   {% endfor %}
 </ul>
 
+<p>Tags:</p>
+<ul>
+  {% for tag in site.tags %}
+    <li>{{ tag[0] }}
+    <ul>
+    {% for page in tag[1] %}
+        <li><a href="{{ page.url }}">{{ page.title }}</a></li>
+    {% endfor %}
+    </ul>
+    </li>
+  {% endfor %}
+</ul>
+
+<p>Categories:</p>
+<ul>
+  {% for category in site.categories %}
+    <li>{{ category[0] }}</li>
+  {% endfor %}
+</ul>
+
 <p>This automatic page generator is the easiest way to create beautiful pages for all of your projects. Author your page content here using GitHub Flavored Markdown, select a template crafted by a designer, and publish. After your page is generated, you can check out the new branch:</p>
 
 <pre><code>$ cd your_repo_root/repo_name