Use importJSON instead of hardcoded require

lib/DatabaseConnectionPool.js

@@ -2,18 +2,12 @@
 
 // Import required modules
 const mysql = require('mysql2/promise');
-const path = require('path');
+
+// Import user defined modules
+const importJSON = require('./importJSON');
 
 // Import the database connection options from config/db.json
-let defaultDbOptions;
-try {
-	defaultDbOptions = require(
-		path.join(__dirname, '../config/db.json'));
-} catch (e) {
-	console.log(e);
-	throw new Error('Missing or malformed config ' +
-		'(config/db.json)');
-}
+const defaultDbOptions = importJSON('db');
 
 /**
  * A class representing a pool of database connections