Include instructions on setting up fzf with fd

[sharkdp]

fzf mentions fd throughout their README 😄 ✨

We should either add a link to fzf and their README or add a little section on how to set up fzf with fd. See also this tutorial: https://mike.place/2017/fzf-fd/

[sharkdp]

I've added some basic instructions here:
https://github.com/sharkdp/fd#using-fd-with-fzf

I found out that fzf can even interpret ansi sequences, so we can do something like this:

export FZF_DEFAULT_COMMAND="fd --type file --follow --color=always"
export FZF_DEFAULT_OPTS="--ansi"

and then (after vim <Ctrl-T>):