Atualizar o bg do topo do site

[fabiocerqueira]

Imagem poderia ser um codigo Python no lugar de CSS :D

https://github.com/pythonNordeste/pyne2018/blob/gh-pages/img/bg-masthead.png

Qualquer codigo desses caras fica bom:

• https://github.com/kennethreitz
• https://github.com/1st1
• https://github.com/njsmith
• https://github.com/norvig
• https://github.com/ramalho
• https://github.com/Lukasa/