Add Nix build for the server #1761

	name: tests

	on:
	push:
	branches: [master]
	pull_request:

	jobs:
	tests:
	runs-on: ubuntu-latest
	env:
	GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
	SPACES_KEY: ${{ secrets.SPACES_KEY }}
	SPACES_SECRET: ${{ secrets.SPACES_SECRET }}
	steps:
	# Setup
	- name: Check out source repository
	uses: actions/checkout@v2

	- name: Cache NPM dependencies
	uses: actions/cache@v2
	with:
	path: ~/.npm
	key: ${{ runner.os }}-node-${{ hashFiles('package-lock.json') }}
	restore-keys: \|
	${{ runner.os }}-node-

	- name: Cache PureScript dependencies
	uses: actions/cache@v2
	with:
	key: ${{ runner.os }}-spago-${{ hashFiles('**/spago.yaml') }}
	path: \|
	.spago
	output
	- name: Install Nix
	uses: DeterminateSystems/nix-installer-action@v4
	with:
	github-token: ${{ env.GITHUB_TOKEN }}

	- name: Setup Nix cache
	uses: DeterminateSystems/magic-nix-cache-action@v2

	# Separates all the cache downloading time from the time required to actually run a step
	# of the workflow
	- name: Initialize Nix
	run: nix develop

	# Checks for the Registry Draft
	- name: "Check that all Dhall compiles, and fixtures correctly conform to a Manifest"
	run: nix develop --command 'registry-verify-dhall'

	- name: "Build project"
	run: nix develop --command 'registry-build'

	- name: "Run tests"
	run: nix develop --command 'registry-test'

	- name: "Verify CI code formats"
	run: nix develop --command 'registry-check-format'

Provide feedback