update docs for intents (#3046)

* update docs for intents

* Fix alexa docs

* Fix api.ai reference

source/developers/intent/index.markdown

@@ -0,0 +1,37 @@
+---
+layout: page
+title: "Intents"
+description: "Intents are helping Home Assistant to gather "
+date: 2017-07-23 20:00
+sidebar: true
+comments: false
+sharing: true
+footer: true
+---
+
+An intent is a description of a user's intention. Intents are generated by user actions, like asking Amazon Echo to turn on a light.
+
+<p class='img'>
+<a href='https://docs.google.com/drawings/d/1i9AsOQNCBCaeM14QwEglZizV0lZiWKHZgroZc9izB0E/edit'><img src='/images/architecture/intents.png' /></a>
+Architectural overview of intents in Home Assistant
+</p>
+
+Intents are fired by components that receive them from external sources/services. Conversation, Alexa, API.ai and Snips are currently sourcing intents.
+
+Any component can handle intents. This makes it very easy for developers to integrate with all voice assistants at once.
+
+Intents are implemented using the `homeassistant.helpers.intent.Intent` class. It contains the following properties:
+
+| Name | Type | Description |
+| ---- | ---- | ----------- |
+| `hass` | Home Assistant | The Home Assistant instance that fired the intent.
+| `platform` | string | The platform that fired the intent
+| `intent_type` | string | The type (name) of the intent
+| `slots` | dictionary | Contains the slot values keyed by slot name.
+| `text_input` | string | Optional. The raw text input that initiated the intent.
+
+Description of the slots dictionary values.
+
+| Name | Type | Description |
+| ---- | ---- | ----------- |
+| Value | anything | Value of the slot.