GarageMate Bluetooth accessory - How to configure?
I have a GarageMate (https://www.bluemate.com/) Bluetooth device that triggers my garage door opener, and I've been able to successfully pair it with my Raspberry Pi running **homebridge**.  Using the **gatttool** utility, I was able to obtain the primary services and characteristics of the GarageMate device.  Now, I'm attempting to update my config.json configuration file with the proper information.  Unfortunately, it's not going well.  The homebridge-bluetooth platform aborts.

GarageMate explained that reading Core Characteristic 0x2A57 from Core Service 0x1815 would activate the device.  These are the UUID values I was able to obtain from gatttool:
```
attr handle: 0x0039, end grp handle: 0xffff uuid: 00001815-0000-1000-8000-00805f9b34fb
handle: 0x003a, char properties: 0x0a, char value handle: 0x003b, uuid: 00002a57-0000-1000-8000-00805f9b34fb
```

The GarageMate implements a momentary contact closure via two wires to the garage door opener.  It doesn't understand in any manner whether the door is open or closed or blocked.  In my understanding, it's a simple button-press.  I'd expect to configure it as follows:

```
"name": "GarageMate",
"address": "01:23:45:67:89:AB",
"services": [ {
    "name": "Garage Door",
    "type": "Automation_IO",
    "UUID": "00001815-0000-1000-8000-00805f9b34fb",
    "characteristics": [ {
        "type": "Button",
        "UUID": "00002a57-0000-1000-8000-00805f9b34fb"
      } ]
   } ]
```
Thank you for your assistance! 
