[Docs] Missing instruction for docker-compose

[innerop]

Hi guys,

In the Quick Start docs, it says:

curl -sSL https://get.docker.com/ | CHANNEL=stable bash

But this does not install docker-compose

You can add something like this to install docker-compose:

Note: docker-compose latest as of this time is 1.26.rc4, so maybe add a note to check the current release

sudo curl -L https://github.com/docker/compose/releases/download/1.25.5/docker-compose-`uname -s`-`uname -m` -o /usr/local/bin/docker-compose

sudo chmod +x /usr/local/bin/docker-compose

I'll fork this if I find other areas to contribute but for now I thought it might be easier to just choose which way you want users to install docker-compose and include that in the docs yourself. This is just a suggestion.