Updated mongo connection to use v3 API

.env.example

@@ -1 +1,2 @@
-MONGO_URL=mongodb://localhost:27017/gurubot2
+MONGO_URL=mongodb://localhost:27017
+MONGO_DB_NAME=gurubot2

src/server/config.js

@@ -9,6 +9,7 @@ if (__DEV__) {
 module.exports = () => ({
     __PROD__,
     __DEV__,
-    mongoUrl: process.env.MONGO_URL || 'mongodb://localhost:27017/gurubot2'
+    mongoUrl: process.env.MONGO_URL || 'mongodb://localhost:27017',
+    mongoDbName: process.env.MONGO_DB_NAME || 'gurubot2'
 });
 

src/server/modules/db.js

@@ -2,10 +2,12 @@ const { MongoClient } = require('mongodb');
 
 async function getDBConnection(config, logger) {
     try {
-        const db = await MongoClient.connect(config.mongoUrl, {
+        const client = await MongoClient.connect(config.mongoUrl, {
             useNewUrlParser: true
         });
 
+        const db = client.db(config.mongoDbName);
+
         logger.verbose('Connected to MongoDB successfully');
 
         return db;