chore(init): project setup with Docker support

backend/.eslintrc.js

@@ -0,0 +1,23 @@
+module.exports = {
+  env: {
+    browser: true,
+    commonjs: true,
+    es2021: true,
+  },
+  extends: 'airbnb-base',
+  overrides: [
+    {
+      env: {
+        node: true,
+      },
+      files: ['.eslintrc.{js,cjs}'],
+      parserOptions: {
+        sourceType: 'script',
+      },
+    },
+  ],
+  parserOptions: {
+    ecmaVersion: 'latest',
+  },
+  rules: {},
+};

backend/.prettierrc.mjs

@@ -0,0 +1,9 @@
+const config = {
+  trailingComma: 'es5',
+  printWidth: 120,
+  tabWidth: 2,
+  semi: true,
+  singleQuote: true,
+};
+
+export default config;

backend/index.js

@@ -0,0 +1,19 @@
+const WebSocket = require('ws');
+
+const wss = new WebSocket.Server({ port: 8080 });
+
+wss.on('connection', (ws) => {
+  console.log('Client connected');
+
+  ws.on('message', (message) => {
+    console.log(`Received message => ${message}`);
+  });
+
+  ws.on('close', () => {
+    console.log('Client disconnected');
+  });
+
+  ws.send('Hello! Message from server.');
+});
+
+console.log('WebSocket server is running on ws://localhost:8080');

backend/package.json

@@ -0,0 +1,22 @@
+{
+  "name": "backend",
+  "version": "1.0.0",
+  "main": "index.js",
+  "scripts": {
+    "dev": "nodemon index.js",
+    "start": "eslint . && node index.js"
+  },
+  "keywords": [],
+  "author": "",
+  "license": "ISC",
+  "description": "",
+  "dependencies": {
+    "eslint": "^8.57.1",
+    "eslint-config-airbnb-base": "^15.0.0",
+    "eslint-plugin-import": "^2.32.0",
+    "ws": "^8.18.3"
+  },
+  "devDependencies": {
+    "prettier": "^3.6.2"
+  }
+}