Rakefile.diff

diff --git a/Rakefile b/Rakefile
index 471b227..06aa580 100644
--- a/Rakefile
+++ b/Rakefile
@@ -25,7 +25,9 @@ posts_dir       = "_posts"    # directory for blog files
 themes_dir      = ".themes"   # directory for blog files
 new_post_ext    = "markdown"  # default new post file extension when using the new_post task
 new_page_ext    = "markdown"  # default new page file extension when using the new_page task
-server_port     = "4000"      # port for preview server eg. localhost:4000
+#server_port     = "4000"      # port for preview server eg. localhost:4000
+server_host     = ENV["IP"] ||= "0.0.0.0"
+server_port     = ENV["port"] ||= ENV["C9_PORT"] ||= "4000"


 desc "Initial setup for Octopress: copies the default theme into the path of Jekyll's generator. Rake install defaults to rake install[classic] to install a different theme run rake install[some_theme_name]"
@@ -79,7 +81,7 @@ task :preview do
   system "compass compile --css-dir #{source_dir}/stylesheets" unless File.exist?("#{source_dir}/stylesheets/screen.css")
   jekyllPid = Process.spawn({"OCTOPRESS_ENV"=>"preview"}, "jekyll --auto")
   compassPid = Process.spawn("compass watch")
-  rackupPid = Process.spawn("rackup --port #{server_port}")
+  rackupPid = Process.spawn("rackup --host #{server_host} --port #{server_port}")

   trap("INT") {
     [jekyllPid, compassPid, rackupPid].each { |pid| Process.kill(9, pid) rescue Errno::ESRCH }