Documentation for Google Calendar component (#1403)

* Documentation for Google Calendar component
* Fixes from @Landrash

source/_components/binary_sensor.google_calendar.markdown

@@ -0,0 +1,115 @@
+---
+layout: page
+title: "Google Calendar Event"
+description: "Instructions how to use Google Calendars in Home Assistant."
+date: 2015-05-08 17:15
+sidebar: true
+comments: false
+sharing: true
+footer: true
+logo: google_calendar.png
+ha_category: Calendar
+ha_iot_class: "Cloud Polling"
+ha_release: 0.33
+---
+
+
+This platform allows you to connect to your [Google Calendars](https://calendar.google.com) and generate binary sensors. The sensors created can trigger based on any event on the calendar or only for matching events. When you first setup this component it will generate a new configuration file *google_calendars.yaml* that will contain information about all of the calendars you can see.
+
+### {% linkable_title Prerequisites %}
+
+Generate a Client ID and Client Secret on [Google Developers Console](https://console.developers.google.com/start/api?id=calendar).
+
+1. Follow the wizard using the following information.
+1. When it gets to the point of asking _Which API are you using?_ just click cancel.
+1. Click on the tab 'OAuth consent screen'.
+1. Set 'Product name shown to users' to anything you want. We suggest Home-Assistant.
+1. Save this page. You don't have to fill out anything else there.
+1. Click 'Create credentials' -> OAuth client ID.
+1. Set the Application type to 'Other' and give this credential set a name then click Create.
+1. Save the client ID and secret as you will need to put these in your configuration.yaml file.
+
+### {% linkable_title Basic Setup %}
+
+To integrate Google Calendar in Home Assistant, add the following section to your `configuration.yaml` file:
+
+```yaml
+# Example configuration.yaml entry
+google:
+  client_id: *Value_created_from_steps_above*
+  client_secret: *Value_created_from_steps_above*
+```
+
+Configuration variables:
+
+- **client_id** (*Required*): Use the value you generated in the Prerequisites stage.
+- **client_secret** (*Required*): Use the value you generated in the Prerequisites stage.
+- **track_new_calendar** (*Optional*): Will automatically generate a binary sensor when a new calendar is detected. The system scans for new calendars on startup. By default this is set to `True`.
+
+The next steps will require you to have Home Assistant running.
+
+After you have it running complete the Google authentication that pops up. It will give you a URL and a code to enter. This will grant your Home Assistant service access to all the Google Calendars that the account you authenticate with can read. This is a Read-Only view of these calendars.
+
+
+### {% linkable_title Calendar Configuration %}
+Editing `google_calendars.yaml`
+
+A basic entry for a single calendar looks like:
+
+```yaml
+- cal_id: "***************************@group.calendar.google.com"
+  entities:
+  - device_id: test_everything
+    name: Give me everything
+    track: true
+- cal_id: "***************************@group.calendar.google.com"
+  entities:
+  - device_id: test_important
+    name: Important Stuff
+    track: true
+    search: "#Important"
+    offset: "!!"
+  - device_id: test_unimportant
+    name: UnImportant Stuff
+    track: true
+    search: "#UnImportant"
+```
+
+Variables:
+
+- **cal_id**: The Google generated unique id for this calendar. **DO NOT CHANGE**
+
+- **entities**: Yes, you can have multiple sensors for a calendar!
+
+  - **device_id**: (*Required*): The name that all your automations/scripts will use to reference this device.
+  
+  - **name**: (*Required*): What is the name of your sensor that you'll see in the frontend.
+  
+  - **track**: (*Required*): Should we create a sensor `True` or ignore it `False`?
+  
+  - **search**: (*Optional*): If set will only trigger for matched events.
+  
+  - **offset**: (*Optional*): A set of characters that precede a number in the event title for designating a pre-trigger state change on the sensor. (Default: `!!`)
+  
+From this we will end up with the binary sensors `calendar.test_unimportant` and `calendar.test_important` which will toggle themselves on/off based on events on the same calendar that match the search value set for each. You'll also have a sensor `calendar.test_everything` that will not filter events out and always show the next event available.
+
+But what if you only wanted it to toggle based on all events? Just leave out the *search* parameter.
+
+**Note**: If you use a `#` sign for search then wrap it up. It's better to be safe!
+
+
+### {% linkable_title Sensor attributes %}
+
+ - **offset_reached**: If set in the event title and parsed out will be `on`/`off` once the offset in the title in minutes is reached. So the title `Very important meeting #Important !!-10` would trigger this attribute to be `on` 10 minutes before the event starts.
+
+ - **all_day**: `True`/`False` if this is an all day event. Will be `False` if there is no event found.
+
+ - **message**: The event title with the `search` and `offset` values extracted. So in the above example for **offset_reached** the **message** would be set to `Very important meeting`
+
+ - **description**: The event description.
+
+ - **location**: The event Location.
+
+ - **start_time**: Start time of event.
+
+ - **end_time**: End time of event.