feat: add tag page

src/content/pages/posts.html

@@ -3,5 +3,14 @@ permalink: /posts/index.html
 layout: "base"
 ---
 
-{% for post in collections.posts %}{{ post.fileSlug }}{% endfor %}
-Here are all my posts!
+<h1>All posts</h1>
+<p>
+    View all <a href="/tags">tags</a>
+</p>
+<ul>
+    {% for post in collections.posts %}
+        <li>
+            <a href={{ post.url }}>{{ post.data.title }}</a>
+        </li>
+    {% endfor %}
+</ul>

src/content/pages/tag.html

@@ -0,0 +1,17 @@
+---
+pagination:
+    data: collections.postsByCategory
+    size: 1
+    alias: tag
+permalink: /tag/{{ tag }}/index.html
+layout: "base"
+---
+
+{% set posts = collections.postsByCategory[tag] %}
+<h1>Tag: {{ tag }}</h1>
+<ul>
+    {% for post in posts %}
+        <li>
+            <a href="{{ post.url }}">{{ post.data.title }}</a>
+        </li>
+    {% endfor %}