feat: add Drizzle ORM support and update README with environment setup and migration scripts

Backend/package.json

@@ -11,6 +11,7 @@
     "@types/jsonwebtoken": "^9.0.10",
     "@types/node": "^25.2.1",
     "@types/pg": "^8.16.0",
+    "drizzle-kit": "^0.31.0",
     "ts-node": "^10.9.2"
   },
   "peerDependencies": {
@@ -22,6 +23,7 @@
     "bcrypt": "^6.0.0",
     "cors": "^2.8.6",
     "dotenv": "^17.2.4",
+    "drizzle-orm": "^0.44.0",
     "express": "^5.2.1",
     "helmet": "^8.1.0",
     "jsonwebtoken": "^9.0.3",
@@ -31,5 +33,13 @@
     "socket.io": "^4.8.3",
     "uuid": "^13.0.0",
     "zod": "^4.3.6"
+  },
+  "scripts": {
+    "start": "bun run index.ts",
+    "dev": "bun --watch index.ts",
+    "db:generate": "drizzle-kit generate",
+    "db:migrate": "drizzle-kit migrate",
+    "db:push": "drizzle-kit push",
+    "db:studio": "drizzle-kit studio"
   }
 }