Docs: a handbook home file is required (#36)

Author: kraftbj

docs/bin/manifest.json

@@ -1,4 +1,9 @@
 {
+    "scf": {
+        "slug": "scf",
+        "parent": null,
+        "markdown_source": "https://github.com/wordpress/secure-custom-fields/blob/trunk/docs/scf.md"
+    },
     "concepts/architecture": {
         "slug": "architecture",
         "parent": "concepts",

docs/scf.md

@@ -0,0 +1,7 @@
+# Welcome to Secure Custom Fields
+
+Secure Custom Fields is a WordPress plugin that allows you to create custom fields for your posts, pages, and custom post types.
+
+## Features
+
+- [Fields](features/fields/index.md) - Create and manage custom fields.