Translate instructions into Spanish

[Jebushdd]

Hi! I find your repo very educative and wanted to make it available for spanish speakers so I just translated the README to Spanish.
I followed the same steps as done in the Chinese translation.

Salu2

[gitname]

Thanks, Jesús (@Jebushdd). If you post a comment containing the URL of the Spanish version of the tutorial, I will update the "Translations" section so it includes a link to that comment (the same as I did for the Chinese version).

[Jebushdd]

https://github.com/Jebushdd/react-gh-pages-es