Try to add tags

http://www.minddust.com/post/tags-and-categories-on-github-pages/ except
step 6 that I don't understand.

_data/tags.yml

@@ -0,0 +1,6 @@
+- slug: finnish
+  name: in Finnish
+- slug: english
+  name: in English
+- slug: irc
+  name: IRC

_layouts/blog_by_tag.html

@@ -0,0 +1,11 @@
+<h1>Articles by tag :{{ page.tag }}</h1>
+<div>
+    {% if site.tags[page.tag] %}
+        {% for post in site.tags[page.tag] %}
+            <a href="{{ post.url }}/">{{ post.title }}</a>
+        {% endfor %}
+    {% else %}
+        <p>There are no posts for this tag.</p>
+    {% endif %}
+</div>
+

_layouts/post.html

@@ -1,6 +1,22 @@
 ---
 layout: default
 ---
+{% if post.tags.size > 0 %}
+    {% capture tags_content %}Posted with {% if post.tags.size == 1 %}<i class="fa fa-tag"></i>{% else %}<i class="fa fa-tags"></i>{% endif %}: {% endcapture %}
+    {% for post_tag in post.tags %}
+        {% for data_tag in site.data.tags %}
+            {% if data_tag.slug == post_tag %}
+                {% assign tag = data_tag %}
+            {% endif %}
+        {% endfor %}
+        {% if tag %}
+            {% capture tags_content_temp %}{{ tags_content }}<a href="/blog/tag/{{ tag.slug }}/">{{ tag.name }}</a>{% if forloop.last == false %}, {% endif %}{% endcapture %}
+            {% assign tags_content = tags_content_temp %}
+        {% endif %}
+    {% endfor %}
+{% else %}
+    {% assign tags_content = '' %}
+{% endif %}
 <div class="post">
 
   <header class="post-header">
@@ -10,6 +26,7 @@ layout: default
 
   <article class="post-content">
     {{ content }}
+    <p id="post-meta">{{ tags_content }}</p>
   </article>
 
 </div>

_posts/2014-12-30-test.md

@@ -2,7 +2,7 @@
 layout: post
 title: Testing...
 category: [english]
-tags: [test, english]
+tags: [english]
 ---
 
 It seems that I started trying the blog feature of Jekyll too.

_posts/2014-12-30-testi.md

@@ -2,7 +2,7 @@
 layout: post
 title: Kokeilua...
 category: [finnish]
-tags: [testi, finnish]
+tags: [finnish]
 ---
 
 Vaikuttaa siltä, että aloitin myös Jekyllin bloggaustoiminnon kokeilun.

_posts/2015-01-10-channels-hostmask-groups-a-basic-howto.md

@@ -2,7 +2,7 @@
 layout: post
 title: "Channels & Hostmask groups: A basic Howto"
 category: [english]
-tags: [oper, irc, groupserv, hostserv]
+tags: [irc, english]
 ---
 
 @Annwenn got me opering at her network after long pause with my opering.

_posts/2015-01-24-getting_help_with_channel_issues.md

@@ -2,7 +2,7 @@
 layout: post
 title: "Getting help from network operators with channel issues when ops are away"
 category: [english]
-tags: [oper, irc, groupserv, hostserv]
+tags: [irc, english]
 ---
 
 In case you wish network operators to help you when your channel operators