docs: Add Hugo Modules docs

docs/content/en/hugo-modules/_index.md

@@ -0,0 +1,24 @@
+---
+title: Hugo Modules
+linktitle: Hugo Modules Overview
+description: How to use Hugo Modules.
+date: 2017-02-01
+publishdate: 2017-02-01
+menu:
+  docs:
+    parent: "modules"
+    weight: 01
+weight: 01
+sections_weight: 01
+categories: [hugo modules]
+keywords: [themes,modules]
+draft: false
+aliases: [/themes/overview/,/themes/]
+toc: true
+---
+
+**Hugo Modules** are the core building blocks in Hugo. A _module_ can be your main project or a smaller module providing one or more of the 7 component types defined in Hugo: **static**, **content**, **layouts**, **data**, **assets**, **i18n**, and **archetypes**.
+
+You can combine modules in any combination you like, and even mount directories from non-Hugo projects, forming a big, virtual union file system.
+
+