Adds uk_transport component documentation (#3037)

* Adds uk_transport documentation

* Update ha_release

source/_components/sensor.uk_transport.markdown

@@ -0,0 +1,122 @@
+---
+layout: page
+title: "UK transport"
+description: "Display the current status of UK train and bus departures."
+date: 2017-07-07 18:00
+sidebar: true
+comments: false
+sharing: true
+footer: true
+logo: train.png
+ha_category: Transport
+ha_iot_class: "Cloud Polling"
+ha_release: "0.50"
+---
+
+
+The `uk_transport` sensor will display the time in minutes until the next departure in a specified direction from of a configured train station or bus stop. The sensor uses [transportAPI](http://www.transportapi.com/) to query live departure data and requires a developer application ID and key which can be obtained [here](https://developer.transportapi.com/). The [free tier](http://www.transportapi.com/plans/) allows 1000 requests daily, which is sufficient for a single sensor refreshing every 87 seconds.
+
+<p class='note warning'>
+Additional sensors can be added but at the expense of a reduced refresh rate. 2 sensors can be updated every 2*87 = 174 seconds, and so on.
+</p>
+
+Queries are entered as a list, with the two transport modes available being `bus` and `train`.
+
+Train departure sensors require three character long `origin` and `destination` station codes which are searchable on the [National Rail enquiries](http://www.nationalrail.co.uk/times_fares/ldb.aspx) website (e.g. `WAT` is London Waterloo). The validity of a route can be checked by performing a GET request to `/uk/train/station/{station_code}/live.json` in the [API reference webpage](https://developer.transportapi.com/docs?raml=https://transportapi.com/v3/raml/transportapi.raml##request_uk_train_station_station_code_live_json).
+
+To add a single train departure sensor add the following to your `configuration.yaml` file:
+
+
+```yaml
+# Example configuration.yaml entry for a single sensor
+sensor:
+  - platform: uk_transport
+    app_id: abc123
+    app_key: efg456
+    queries:
+      - mode: train
+        origin: MAL
+        destination: WAT
+```
+
+Configuration variables:
+
+- **app_id** (*Required*): Your application id
+- **app_key** (*Required*): Your application key
+- **queries** array (*Required*): At least one entry required.
+- **mode** (*Required*): One of `bus` or `train`.
+- **origin** (*Required*): Specify the three character long origin station code.
+- **destination** (*Required*): Specify the three character long destination station code.
+
+A large amount of information about upcoming departures is available within the attributes of the sensor. The example above creates a sensor with ID `sensor.next_train_to_wat` with the attribute `next_trains` which is a list of the next 25 departing trains. The status of the next departing train is accessed using the [template sensor](https://home-assistant.io/components/sensor.template/) below, as are the train origin, estimated and scheduled departure times, and the departure platform.
+
+```yaml
+# Example configuration.yaml entry for a template sensor to access the attributes of the next departing train.
+- platform: template
+  sensors:
+    next_train_status:
+      friendly_name: 'Next train status'
+      value_template: '{{states.sensor.next_train_to_wat.attributes.next_trains[0].status}}'
+    next_trains_origin:
+      friendly_name: 'Next train origin'
+      value_template: '{{states.sensor.next_train_to_wat.attributes.next_trains[0].origin_name}}'
+    next_trains_estimated:
+      friendly_name: 'Next train estimated'
+      value_template: '{{states.sensor.next_train_to_wat.attributes.next_trains[0].estimated}}'
+    next_trains_scheduled:
+      friendly_name: 'Next train scheduled'
+      value_template: '{{states.sensor.next_train_to_wat.attributes.next_trains[0].scheduled}}'
+    next_trains_platform:
+      friendly_name: 'Next train platform'
+      value_template: '{{states.sensor.next_train_to_wat.attributes.next_trains[0].platform}}'
+
+```
+
+Bus sensors require as their `origin` a bus stop ATCO code which can be found by browsing OpenStreetMap data as
+follows:
+
+1. On [OpenStreetMap.org](http://www.openstreetmap.org/) zoom right in on a bus
+stop you're interested in
+2. Click the layers picker button on the right hand side
+3. Tick the 'map data' layer, and wait for clickable objects to load
+4. Click the bus stop node to reveal its tags on the left
+
+The `destination` must be a valid location returned by the transportAPI query. Valid destinations can be checked by performing a GET query to  `/uk/bus/stop/{atcocode}/live.json` in the [API reference webpage](https://developer.transportapi.com/docs?raml=https://transportapi.com/v3/raml/transportapi.raml##bus_information). A bus sensor is added in the following `configuration.yaml` file entry:
+
+```yaml
+# Example configuration.yaml entry for multiple sensors
+sensor:
+  - platform: uk_transport
+    app_id: abc123
+    app_key: efg456
+    queries:
+      - mode: bus
+        origin: 340000368SHE
+        destination: Wantage
+      - mode: train
+        origin: MAL
+        destination: WAT
+```
+
+And the template sensor for viewing the next bus attributes.
+
+```yaml
+# Example configuration.yaml entry for a template sensor to access the attributes of the next departing bus.
+- platform: template
+  sensors:
+    next_bus_route:
+      friendly_name: 'Next bus route'
+      value_template: '{{states.sensor.next_bus_to_wantage.attributes.next_buses[0].route}}'
+    next_bus_direction:
+      friendly_name: 'Next bus direction'
+      value_template: '{{states.sensor.next_bus_to_wantage.attributes.next_buses[0].direction}}'
+    next_bus_scheduled:
+      friendly_name: 'Next bus scheduled'
+      value_template: '{{states.sensor.next_bus_to_wantage.attributes.next_buses[0].scheduled}}'
+    next_bus_estimated:
+      friendly_name: 'Next bus estimated'
+      value_template: '{{states.sensor.next_bus_to_wantage.attributes.next_buses[0].estimated}}'
+
+```
+
+Powered by [transportAPI](http://www.transportapi.com/)