Add docs for Sensirion SHT31 sensor (#4848)

source/_components/sensor.sht31.markdown

@@ -0,0 +1,52 @@
+---
+layout: page
+title: "Sensirion SHT31 Sensor"
+description: "Instructions on how to integrate SHT31 sensors within Home Assistant."
+date: 2018-03-06 19:15
+sidebar: true
+comments: false
+sharing: true
+footer: true
+ha_category: DIY
+ha_release: 0.68
+logo: sensirion.png
+ha_iot_class: "Local Polling"
+---
+
+The `sht31` sensor platform allows you to get the current temperature and humidity from a Sensirion SHT31 device.
+
+To use your SHT31 sensor in your installation, add the following to your `configuration.yaml` file:
+
+```yaml
+# Example configuration.yaml entry
+sensor:
+  platform: sht31
+  name: Bedroom
+  i2c_address: 0x44
+  monitored_conditions:
+    - temperature
+    - humidity
+```
+
+{% configuration %}
+  name:
+    description: The name of the sensor. Temperature and Humidity will be added to the name for the sensor name.
+    required: false
+    default: SHT31
+    type: string
+  i2c_address:
+    description: I2C address of the sensor.
+    required: false
+    default: "`0x44`"
+    type: int
+  monitored_conditions:
+    description: Conditions to monitor.
+    required: false
+    default: All conditions
+    type: list
+    keys:
+      temperature: 
+        description: The current temperature of the SHT31.
+      humidity:
+        description: The current humidity of the SHT31.
+{% endconfiguration %}