CORS headers not sent

[benburwell]

When I try to use XMLHttpRequest to POST data to /api/events, I get an error related to CORS in the browser console.

I was able to solve the issue by adding the cors package and using it as a middleware for express (just adding app.use(cors()); to index.js).

It seems like this would be a fairly common use case and I was surprised that this isn't set up out-of-the box. Is this something that should be added? If so, I'd be happy to submit a PR.

Thanks!