added index controller to test connection with server

src/controllers/indexController.js

@@ -0,0 +1,17 @@
+/**
+ * Sends a message as a response to inform user that server is working
+ * @param {Object} req 
+ * @param {Object} res 
+ * @param {Function} next 
+ */
+const indexController = (req, res, next) => {
+    const result = {
+		_data: {
+			message: 'Server up!'
+		}
+	}
+
+	next(result)
+}
+
+export { indexController }