Integrated the database into the app.ts & added the start method

app.ts

@@ -1,3 +1,18 @@
+import mongoose, {CallbackError} from 'mongoose';
+import * as api from './server/api';
+
 // Load & check environment
 require('dotenv').config();
-require('./util/envCheck').validate();
+require('./util/envCheck').validate();
+
+// Connect to database
+mongoose.connect(process.env.MONGOOSE_STRING || '', (e: CallbackError) => {
+    if (e) throw new Error(`Could not connect to database: ${e.message}`);
+    console.log("[DB] Successfully connected to the database");
+    start();
+});
+
+// Start all servers
+const start = () => {
+    api.startServer(parseInt(process.env.API_PORT || ''));
+}