feat(express backend): basic structure implemented

back-express/package.json

@@ -0,0 +1,26 @@
+{
+  "name": "express-backend",
+  "version": "1.0.0",
+  "scripts": {
+    "dev": "nodemon src/app.ts",
+    "start": "ts-node src/app.ts",
+    "build": "tsc",
+    "serve": "node dist/app.js"
+  },
+  "author": "Daniel Heras Quesada",
+  "license": "ISC",
+  "description": "",
+  "devDependencies": {
+    "@types/cors": "^2.8.17",
+    "@types/express": "^5.0.0",
+    "@types/node": "^22.7.4",
+    "express": "^4.21.0",
+    "nodemon": "^3.1.7",
+    "ts-node": "^10.9.2",
+    "typescript": "^5.6.2"
+  },
+  "dependencies": {
+    "cors": "^2.8.5",
+    "dotenv": "^16.4.5"
+  }
+}