Use GitHub email api to get email address of user

[leafo]

user.email is only available if the account has a publicly listed email address. You'll need to use the emails api endpoint to fetch the email address: https://developer.github.com/v3/users/emails/

I added a temporary message but we should fetch their email so anyone can log in: https://github.com/luarocks/luarocks-site/blob/2ad70c3e59dceaa61225f875e1e74579f4a1ef07/applications/github.moon#L73

[aajjbb]

somehow the commit that address this issue is in the #114. I don't know how this happened.

[leafo]

aajjbb do you want to pull the commit out into seprate pull request?

[aajjbb]

This seems much wiser.

[aajjbb]

Closed via #116