Publish your jeykll _site files to master so that you can build out your jekyll plugins for uses with github pages. Source from http://ixti.net/software/2013/01/28/using-jekyll-plugins-on-github-pages.html

Rakefile

require "jekyll"
require 'tmpdir'

GITHUB_REPONAME = "digitalcake/digitalcake.github.com"
SOURCE = "."
CONFIG = {
  'layouts' => File.join(SOURCE, "_layouts"),
  'posts' => File.join(SOURCE, "_posts")
}


desc "Generate blog files"
task :generate do
  Jekyll::Site.new(Jekyll.configuration({
    "source"      => ".",
    "destination" => "_site"
  })).process
end


desc "Generate and publish blog to gh-pages"
task :publish => [:generate] do
  Dir.mktmpdir do |tmp|
    cp_r "_site/.", tmp
    Dir.chdir tmp
    system "git init"
    system "git add ."
    message = "Site updated at #{Time.now.utc}"
    system "git commit -m #{message.shellescape}"
    system "git remote add origin git@github.com:#{GITHUB_REPONAME}.git"
    system "git push origin master --force"
  end
end