README: Add paragraph on motivation #9

	on: push

	jobs:
	checks:
	name: Elixir ${{matrix.elixir}} / OTP ${{matrix.otp}}
	runs-on: ubuntu-20.04

	strategy:
	matrix:
	elixir: [1.13.4]
	otp: [24.1.7]

	services:
	postgres:
	image: postgres:13
	env:
	POSTGRES_USER: postgres
	POSTGRES_PASSWORD: postgres
	POSTGRES_DB: refinery_test
	ports:
	- 5432:5432
	options: --health-cmd pg_isready --health-interval 10s --health-timeout 5s --health-retries 5

	env:
	MIX_ENV: test

	steps:
	- uses: actions/checkout@v2

	- name: Setup Erlang & Elixir
	uses: erlef/setup-beam@v1
	with:
	elixir-version: ${{ matrix.elixir }}
	otp-version: ${{ matrix.otp }}

	# Caching
	- name: Dependencies cache
	uses: actions/cache@v1
	with:
	path: deps
	key: ${{ runner.os }}-deps-${{ hashFiles('mix.lock') }}
	restore-keys: \|
	${{ runner.os }}-deps-${{ hashFiles('mix.lock') }}

	- name: Build cache
	uses: actions/cache@v1
	with:
	path: _build
	key: ${{ runner.os }}-build-test-${{matrix.elixir}}-${{matrix.otp}}-${{ hashFiles('mix.lock') }}
	restore-keys: \|
	${{ runner.os }}-build-test-${{matrix.elixir}}-${{matrix.otp}}-

	# Setup
	- name: Install dependencies
	run: mix deps.get

	# Checks
	- name: Compiler warnings (test)
	run: mix compile --warnings-as-errors --force

	- name: Test suite
	run: mix test
	env:
	WARNINGS_AS_ERRORS: "true"

	- name: Code format
	run: mix format --check-formatted --dry-run

Provide feedback