Run requestbin and ngrok for local webhook debugging

docker-compose.yml

version: '3.3'
services:
    ngrok:
        image: wernight/ngrok
        ports:
            - '4040:4040'
        links:
            - httpbin
        command: ngrok http httpbin:80
    httpbin:
        container_name: httpbin
        image: kennethreitz/httpbin
        ports:
            - '8000:80'