Add v4, with proxy, app and db

bulletin-board-app/backend/db.js

@@ -0,0 +1,34 @@
+var Sequelize = require('sequelize');
+var username = 'sa';
+var password = 'DockerCon!!!';
+var host = 'bb-db';
+var dbName = 'BulletinBoard';
+
+var sequelize = new Sequelize(dbName, username, password, {
+    dialect: 'mssql',
+    host: host,
+    port: 1433,
+    dialectOptions: {
+        requestTimeout: 30000
+    }
+});
+
+sequelize
+    .authenticate()
+    .then(() => {
+        console.log('Successful connection to SQL Server.');
+    })
+    .catch(err => {
+        console.error('** SQL Server connection failed: ', err);
+        process.exit(1);
+    });
+
+var Event = sequelize.define('event', {
+    title: Sequelize.STRING,
+    detail: Sequelize.STRING,
+    date: Sequelize.DATE
+});
+
+Event.sync();
+
+exports.Events = Event;