Add site.github.private_repositories field

This creates a GET request to /user/repos with type set to `private`.
See https://developer.github.com/v3/repos/#list-your-repositories for more
information.

fixes jekyll#23

lib/jekyll-github-metadata.rb

@@ -81,6 +81,7 @@ def init!
 
         # The Juicy Stuff
         register_value('public_repositories',  proc { |_,r| r.owner_public_repositories })
+        register_value('private_repositories', proc { |_,r| r.accessible_private_repositories  })
         register_value('organization_members', proc { |_,r| r.organization_public_members })
         register_value('build_revision',       proc {
           ENV['JEKYLL_BUILD_REVISION'] || `git rev-parse HEAD`.strip

lib/jekyll-github-metadata/repository.rb

@@ -72,6 +72,10 @@ def owner_public_repositories
         memoize_value :@owner_public_repositories, Value.new(proc { |c| c.list_repos(owner, "type" => "public") })
       end
 
+      def accessible_private_repositories
+        memoize_value :@accessible_private_repositories, Value.new(proc { |c| c.list_repos(nil, "type" => "private") })
+      end
+
       def organization_public_members
         memoize_value :@organization_public_members, Value.new(proc { |c|
           c.organization_public_members(owner) if organization_repository?

spec/integration_spec.rb

@@ -22,6 +22,7 @@ def initialize(path, file)
 
   API_STUBS = {
     "/users/jekyll/repos?per_page=100&type=public"            => "owner_repos",
+    "/user/repos?per_page=100&type=private"                   => "accessible_private_repos",
     "/repos/jekyll/github-metadata"                           => "repo",
     "/orgs/jekyll"                                            => "org",
     "/orgs/jekyll/public_members?per_page=100"                => "org_members",