indexes support for tags,categories,authors

[noraj]

Feature

I added indexes for

• tags: http://example.org/tags/
• categories: http://example.org/categories/
• authors: http://example.org/author/

One need to create those files.

source/author/index.md

---
title: Authors
layout: "authors"
---

source/tags/index.md

---
title: Tags
layout: "tags"
---

source/categories/index.md

---
title: Categories
layout: "categories"
---

Screenshots