Gel to support GitHub flag

[venarius]

I really like the feature of bundler to easily clone repos from GitHub by specifying the repository path using the github flag:

gem 'nokogiri', :github => 'tenderlove/nokogiri'

Would be awesome if Gel also supports that feature. Since I already said that I want to get more involved into this project, I can also try adding support for that flag 👍

[matthewd]

Yes please!

It already support's Bundler's new recommended format, where you first define it in your Gemfile:

git_source(:github) { |repo_name| "https://github.com/#{repo_name}" }

.. but I think it'd be neat to have built-in support for :github, as Old-Time Bundler once did.

For compatibility, it would probably need to use the same URL format as Old Bundler in the lockfile, but should automatically use https internally.