[Suggestion for flyio-cloud-dev-env] Set iptables = false for docker get working

[hacker-hackman]

Currently if one tries to run docker (even with sudo) in this cloud env at fly.io there is an error:
Cannot connect to the Docker daemon at unix:///var/run/docker.sock. Is the docker daemon running?

To fix it:

1. Create a file /etc/docker/daemon.json containing:

{
  "iptables": false
}

2. Run service docker start

Sources:
https://forums.docker.com/t/failing-to-start-dockerd-failed-to-create-nat-chain-docker/78269/2
https://forums.docker.com/t/failing-to-start-dockerd-failed-to-create-nat-chain-docker/78269/9
https://gist.github.com/goll/bdd6b43c2023f82d15729e9b0067de60

Thanks for a great job by the way! You've made what I'm exactly was looking for since the last week :-)

[lambrospetrou]

Nice. I will keep it in mind in my next update and add it in the setup code!