Include instructions on CORS Handling

[cjlludwig]

Big fan of this framework but it seems like it's ideal usage is for personal projects where CORs issues may come up pretty frequently. Information on handling CORs issues in a Github hosted React page would be very helpful for these cases.

[gitname]

Hi @cjlludwig,

I noticed you mentioned a "framework". I want to make sure this is the repository you meant to open this issue in. Will you confirm? I've never thought of this project as a framework before, but I can see how someone could think of it as one (e.g. the deployed React app the reader ends up with could serve as a basis for the "real" app they want to build).

I normally think of CORS as something configured on the server side. Are you suggesting that this tutorial be updated to remind the reader that they may have to configure CORS on the web server their React app sends HTTP request to?

[cjlludwig]

I probably use framework a little loosely here but see it as a custom tool to speed deploying to Github Pages so I think there's some merit to it.

CORs still comes into play when trying to request content dynamically on the Github page. Link previews, etc. I know GIthub Pages probably is the better source of info there but figured it might be a nice addition for a common question.

Really nice work on this project!