Added support for private repositories

[dominiklessel]

This PR allows to set two new environment variables to enable support for private repos:

• GH_TOKEN - GitHub personal access token needed to access the private repo.
• PRIVATE_BASE_URL - Base URL of the update server (e.g. update.example.com).

Both are required to make hazel work with private repos.

The proxyPrivateDownload helper found in routes.js uses node-fetch to proxy the private file through hazel. This obviously leads to higher server load and increased bandwidth usage, but should be okay for this specific use case 😸

[leo]

Looks really good! 😲 Just a few things:

• GH_TOKEN => TOKEN
• PRIVATE_BASE_URL => URL

Can we also add support for Now's NOW_URL environment flag (which contains the URL of the current deployment)?

[leo]

Can you remove all of this after here? I don't see how it's necessary.

[dominiklessel]

Sure, will do. Just added it for internal testing purposes

[dominiklessel]

Just updated the PR 👨‍🔧

[leo]

Thank you so much! 😍

[dominiklessel]

Nice! Thank you for merging 😃

[zeke]

Thanks, @dominiklessel!

[karanjthakkar]

@leo This was unfortunately broken with this commit For private repos, browser_download_url is not used. The url from the asset object is also needed. Would you accept a PR which doesn't break #26 but also supports this?

[leo]

@karanjthakkar Yep. That would be wonderful!

[apurvaSynerzip]

@dominiklessel @leo Can you share working example for Github private repo?