Setup a guide for translation contribution

[Penfore]

I would like to contribute with translations to Brazilian Portuguese.

Please, consider adding a guide to this type of contributions.

[le-jun]

I think localization is still a stub at this point, it seems one could translate the whole thing through this directory:

• Create a folder for your language using the 2 letters code
• Copy and modify the content of the en folder
• Pull Request.