Added more logging for mongo db.

src/database/mongo.js

@@ -44,6 +44,14 @@ class MongoServer {
     }
     return mongoose.connection;
   }
+
+  async disconnect() {
+    if (!this.connected) return;
+    logger.info('Disconnecting from MongoDB...');
+    await mongoose.connection.close();
+    this.connected = false;
+    logger.info('Disconnected from MongoDB');
+  }
 }
 
 const mongoServer = new MongoServer();