Prepare application for deployment using Docker containers

Adds Dockerfile, docker-compose.yml, .dockerignore, nginx.conf, init.sql and updates replit.md and server/routes.ts.

Replit-Commit-Author: Agent
Replit-Commit-Session-Id: 91318273-c764-4fd4-be04-bdc12c38af32
Replit-Commit-Screenshot-Url: https://storage.googleapis.com/screenshot-production-us-central1/0715008c-7244-40f4-befc-26c014852236/c3a86207-4ee0-47f9-8062-2dbbae696290.jpg

server/routes.ts

@@ -117,6 +117,16 @@ export async function registerRoutes(app: Express): Promise<Server> {
     }
   });
 
+  // Health check endpoint for Docker
+  app.get('/health', (req, res) => {
+    res.status(200).json({
+      status: 'healthy',
+      timestamp: new Date().toISOString(),
+      uptime: process.uptime(),
+      environment: process.env.NODE_ENV || 'development'
+    });
+  });
+
   app.get('/api/auth/me', requireAuth, async (req, res) => {
     try {
       const user = await storage.getUser(req.session.userId!);