Update development setup instructions (#313)

* Add step about requiring patrons.json file

* Update steps to get DB up and running

* Clarify Discord login setup instructions

* Clarify how to start/stop server for new developers

* Update README to remove unneeded .env.local var

Co-authored-by: Kalle <38327916+Sendouc@users.noreply.github.com>

prisma/scripts/preBuild.ts

@@ -2,6 +2,9 @@ import fs from "fs";
 import path from "path";
 import prisma from "../client";
 
+// Include Prisma's .env file as well, so we can fetch the DATABASE_URL
+require('dotenv').config({path: 'prisma/.env'});
+
 const main = async () => {
   const patrons = await prisma.user.findMany({
     where: { patreonTier: { not: null } },