Added Contributors section to the readme.

Author: jburhenn

README.md

@@ -15,3 +15,7 @@ This library bundles the [Eclipse Paho MQTT C/C++ client](https://github.com/ecl
 - **[Cayenne-MQTT-CPP](https://github.com/myDevicesIoT/Cayenne-MQTT-CPP)** - C++ version of the Cayenne MQTT Library.
 - **[Cayenne-MQTT-Arduino](https://github.com/myDevicesIoT/Cayenne-MQTT-Arduino)** - Arduino version of the Cayenne MQTT Library.
 - **[Cayenne-MQTT-mbed](https://github.com/myDevicesIoT/Cayenne-MQTT-mbed)** - mbed version of the Cayenne MQTT Library. This is also available on the mbed developer site [here](https://developer.mbed.org/teams/myDevicesIoT/code/Cayenne-MQTT-mbed/).
+
+## Contributors
+Contributions to this library have been made by the following people.
+- Rei Vilo (rei-vilo)