Update Hass.io docs

source/developers/hassio/addon_repository.markdown

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+---
+layout: page
+title: "Create an add-on repository"
+description: "Add-ons repositories."
+date: 2017-04-30 13:28
+sidebar: true
+comments: false
+sharing: true
+footer: true
+redirect_from: /hassio/addon_repository/
+---
+
+Add-ons repository can contain one or more add-ons. Each add-on is stored in it's own unique folder. For it to be indentified as a repository, a repository contains a configuration file.
+
+[Example add-on repository](https://github.com/home-assistant/hassio-addons-example).
+
+## Installing a repository
+
+A user can add a repository by going to the Hass.io panel in Home Assistant, clicking on the store icon in the top right, copy/paste the URL of your repostory into the repository textarea and click on "Save".
+
+## Repository configuration
+
+Each repository is required to contain `repository.json` at the root of the Git repository.
+
+```json
+{
+  "name": "Name of repository",
+  "url": "http://www.example/addons",
+  "maintainer": "HomeAssistant Team <info@home-assistant.io>"
+}
+```
+
+| Key | Required | Description |
+| --- | -------- | ----------- |
+| name | yes | Name of the repository
+| url | no | Homepage of the repository. Here you can explain the various add-ons.
+| maintainer | no | Contact info of the maintainer.