Add The Things Network documentation (#3465)

* Add The Things Network documentation

* Fix date

* Rename sensor platform

source/_components/sensor.thethingsnetwork.markdown

@@ -0,0 +1,79 @@
+---
+layout: page
+title: "The Things Network Sensor"
+description: "Instructions how to integrate The Things Network sensors into Home Assistant."
+date: 2017-09-30 08:00
+sidebar: true
+comments: false
+sharing: true
+footer: true
+logo: thethingsnetwork.png
+ha_category: Sensor
+ha_iot_class: "Local Polling"
+ha_release: 0.55
+---
+
+The `thethingsnetwork` sensor platform allows you to get data from a [The Things Network Storage Integration](https://www.thethingsnetwork.org/docs/applications/storage/).
+
+This platform requires that the [The Things Network component](/components/thethingsnetwork/) is set up and the [The Things Network Storage Integration](https://www.thethingsnetwork.org/docs/applications/storage/) as well.
+
+Visit the [The Things Network Console](https://console.thethingsnetwork.org/) website, log in with your The Things Network credentials, choose your application from **Applications** and go to **Integrations**.
+
+Add a new integration.
+
+<p class='img'>
+<img src='/images/components/thethingsnetwork/add_integration.png' />
+Add a The Things Network integration
+</p>
+
+Select **Data Storage**.
+
+<p class='img'>
+<img src='/images/components/thethingsnetwork/choose_integration.png' />
+Choose a The Things Network integration
+</p>
+
+Click **Add integration** to finish the process.
+
+<p class='img'>
+<img src='/images/components/thethingsnetwork/confirm_integration.png' />
+Add a The Things Network Data Storage integration
+</p>
+
+When done, the status of the integration should be **Running**. You could check the output after clicking on **go to platform** in an interactive web interface. 
+
+<p class='img'>
+<img src='/images/components/thethingsnetwork/storage_integration.png' />
+Add a The Things Network integration
+</p>
+
+Select **Devices** to get the ID of your device that you want to use.
+
+<p class='img'>
+<img src='/images/components/thethingsnetwork/devices.png' />
+Devices overview
+</p>
+
+To enable this platform, add the following lines to your `configuration.yaml`:
+
+```yaml
+# Example configuration.yaml entry
+sensor:
+  - platform: thethingsnetwork
+    device_id: ha-demo
+    values:
+      sensor_value: unit of measurment
+      voltage: V
+```
+
+{% configuration %}
+  device_id:
+    description: The ID of the device.
+    required: true
+    type: string
+  values:
+    description: The sensor values with their unit of measurement
+    required: true
+    type: list
+{% endconfiguration %}
+