Merge pull request #653 from torhovland/patch-1

Add missing require.

Author: niftylettuce

Diff for: README.md

@@ -34,6 +34,7 @@ test framework at all:
 
 ```js
 const request = require('supertest');
+const assert = require('assert');
 const express = require('express');
 
 const app = express();