Add Sentrius RG1XX install docs.

Author: brocaar

docs/content/install/gateway/_index.md

@@ -14,6 +14,7 @@ menu:
 Instructions are available for the following vendors:
 
 * [Kerlink]({{<relref "kerlink.md">}})
+* [Laird]({{<relref "laird.md">}})
 * [MatchX]({{<relref "matchx.md">}})
 * [Multitech]({{<relref "multitech.md">}})
 

docs/content/install/gateway/laird.md

@@ -0,0 +1,33 @@
+---
+title: Laird
+menu:
+    main:
+      parent: gateway
+---
+
+## Laird
+
+### Sentrius RG1XX LoRa gateway
+
+**Note:** The LoRa Gateway Bridge component comes pre-installed since firmware version
+[93.7.2.9](https://assets.lairdtech.com/home/brandworld/files/CONN-RN-RG1xx-laird-93_7_2_9.pdf).
+If your gateway is running an older version, please update it first.
+
+The pre-installed LoRa Gateway Bridge can be configured through the gateway
+web-interface using the following steps:
+
+* Login into the gateway web-interface
+* In the top navigation bar, click on **LoRa**
+* In the left navigation menu, click **Forwarder**
+* From the *Mode* dropdown, select **MQTT Forwarder**
+* Enter your MQTT **Server Address** and optionally the MQTT **Username** and **Password**
+
+Please see [configuration]({{<ref "install/config.md">}}) for valid
+configuration options. The fields map to the following configuration options:
+
+* Server Address:  `--mqtt-server`
+* Username: `--mqtt-username`
+* Password: `--mqtt-password`
+
+For more information about this gateway:
+[https://www.lairdtech.com/products/rg1xx-lora-gateway](https://www.lairdtech.com/products/rg1xx-lora-gateway)