Update mosquitto.markdown

source/_addons/mosquitto.markdown

@@ -9,4 +9,22 @@ sharing: true
 footer: true
 ---
 
-[Placeholder]
+Setup a [mosquitto](https://mosquitto.org/) mqtt broker.
+
+```json
+{
+  "plain": true,
+  "ssl": false,
+  "anonymous": true,
+  "logins": [
+    {"username": "testuser", "password": "mypw"}
+  ]
+}
+```
+
+Configuration variables:
+
+- **plain** (*Optional*): default true. Listen broaker on port 1883 without SSL/TLS.
+- **ssl** (*Optional*): default false. Listen broker on port 8883 with SSL/TLS. Need to have certificates.
+- **anonymous** (*Optional*): default true. Allow anonymous connection. If *logins* is set, anonymous user can only read data.
+- **logins** (*Optional*): default empty. A list of user that will be create with *username* and *password*.