add docs for sochain sensor (#4287)

* add sochain documentation

* Minimize configuration sample

source/_components/sensor.sochain.markdown

@@ -0,0 +1,50 @@
+---
+layout: page
+title: "SoChain"
+description: "Instructions how to integrate chain.so data within Home Assistant."
+date: 2017-06-01 16:20
+sidebar: true
+comments: false
+sharing: true
+footer: true
+logo: sochain.png
+ha_category: Finance
+ha_release: 0.61
+ha_iot_class: "Cloud Polling"
+---
+
+
+The `SoChain` sensor platform displays supported cryptocurrency wallet balances from [SoChain](https://chain.so).
+
+To add the SoChain sensor to your installation, specify a network and address to watch in the `configuration.yaml` file:
+
+```yaml
+# Example configuration.yaml entry
+sensor:
+  - platform: sochain
+    network: LTC
+    address: 'M9m37h3dVkLDS13wYK7vcs7ck6MMMX6yhK'
+```
+
+{% configuration %}
+network:
+  description: The network or blockchain of the cryptocurrency to watch.
+  required: true
+  type: string
+address:
+  description: Cryptocurrency wallet address to watch.
+  required: true
+  type: string
+name:
+  description: The name of the sensor used in the frontend. (recommended)
+  required: false
+  type: string
+  default: Crypto Balance
+{% endconfiguration %}
+
+Supported networks (which can also be found [here](https://chain.so/api#networks-supported)) are:
+
+* BTC
+* LTC
+* DOGE
+* DASH