ctx.body after exec not working (
The next code **returns ERR_EMPTY_RESPONSE in browser**  ((( 

```
const Koa = require('koa');
const router = require('koa-route');
const util = require('util');
const exec = util.promisify(require('child_process').exec);

const app = new Koa();

app.use(router.get('/deploy', async (ctx, projectName) => {
    const { stdout, stderr } = await exec('cd /opt/webserver/face-and-deploy && git pull origin master && npm i && pm2 restart face-and-deploy');
console.log(stderr ? stderr : stdout);    
ctx.body = stderr ? stderr : stdout;  
}));

app.use(async ctx => ctx.body = 'Hello, world!');
app.listen(80);
```

In pm2 logs - wrong info too:

> 20|face-and-deploy  | listening on port80

**what is wrong !!!???**

Enwironment: Ubuntu 18, node 9.2 
