Fix rebar3 mentions in the README

[whatyouhide]

There is no rebar3 executable in this repository, nor is one installed by any of the commands in the README. Some of us use the rebar3 executable that is installed by Hex, others use the asdf plugin, and this section from Rebar's official website even says:

While the script version of Rebar3 is portable and usable from anywhere, it is advised not to keep it in your project’s repository and to install it globally, for your entire system. Regardless of which recent Erlang version you have installed, Rebar3 should be fully compatible with it.

So I'd say we instruct folks to do rebar3 instead of ./rebar3. Thoughts?

[whatyouhide]

I don't think we want to mention overmind, which seems to be a tool that requires auth and whatnot. Am I missing something?

[weppos]

We use Overmind as process management across most of our apps.
https://github.com/DarthSim/overmind

It is reading the Procfile, which is a sort of standard process definition
https://github.com/dnsimple/erldns/blob/main/Procfile

It's a sort of convention. However, we generally wrap it behind a convenient make call:

make start

I imagine we have not cleaned it up for Erlang projects yet. Do you have an alternative recommendation on how to start the app, that could work consistently across the various apps?

[whatyouhide]

No wonder I was confused... I thought this was about this overmind CLI tool. 🤦

Ok, makes sense then. Yep, I’m familiar with Procfiles and all. I'll make sure that we have make start here and maybe a note about overmind then. I'll close this PR out.

[weppos]

nor is one installed by any of the commands in the README.

Actually, it is installed by make the first time you will call any task that need rebar (vs calling rebar directly).

erldns/Makefile

Lines 1 to 7 in 5ce0b25

	REBAR:=$(shell which rebar3 || echo ./rebar3)
	REBAR_URL:="https://s3.amazonaws.com/rebar3/rebar3"
	all: clean build
	$(REBAR):
	curl -o rebar3 $(REBAR_URL) && chmod +x rebar3

Perhaps this part should be made more explicitly documented in our repo.

I suspect rebar should work with both local and global setups, whereas the opposite is not true (aka ./rebar). Correct?

[whatyouhide]

From this line

REBAR:=$(shell which rebar3 || echo ./rebar3)

then yeah it looks like a globally-installed rebar3 would take precedence over the locally-installed, which is what we want I think. I'll rework this in a different PR 🙃