Migrate storage from in-memory to PostgreSQL database.

Replit-Commit-Author: Agent
Replit-Commit-Session-Id: 9111ef36-26c8-4085-84ca-a35dc1fec1b5
Replit-Commit-Screenshot-Url: https://storage.googleapis.com/screenshot-production-us-central1/7083d608-d6d3-4a6a-9a27-6286c5109627/37883948-9924-4429-8878-f2530cf6fe2b.jpg

server/db.ts

@@ -0,0 +1,15 @@
+import { Pool, neonConfig } from '@neondatabase/serverless';
+import { drizzle } from 'drizzle-orm/neon-serverless';
+import ws from "ws";
+import * as schema from "@shared/schema";
+
+neonConfig.webSocketConstructor = ws;
+
+if (!process.env.DATABASE_URL) {
+  throw new Error(
+    "DATABASE_URL must be set. Did you forget to provision a database?",
+  );
+}
+
+export const pool = new Pool({ connectionString: process.env.DATABASE_URL });
+export const db = drizzle(pool, { schema });