More robust site:publish.

Rakefile

@@ -133,28 +133,38 @@ namespace :site do
     sh "cd site && jekyll --server"
   end
 
-  desc "Commit the local site to the gh-pages branch and deploy"
+  desc "Commit the local site to the gh-pages branch and publish to GitHub Pages"
   task :publish do
     # Ensure the gh-pages dir exists so we can generate into it.
     puts "Checking for gh-pages dir..."
     unless File.exist?("./gh-pages")
       puts "No gh-pages directory found. Run the following commands first:"
-      puts "  `git clone git@github.com:mojombo/god gh-pages"
+      puts "  `git clone git@github.com:mojombo/jekyll gh-pages"
       puts "  `cd gh-pages"
       puts "  `git checkout gh-pages`"
       exit(1)
     end
 
-    # Copy the rest of the site over.
+    # Ensure gh-pages branch is up to date.
-    puts "Copying static..."
+    Dir.chdir('gh-pages') do
+      sh "git pull origin gh-pages"
+    end
+
+    # Copy to gh-pages dir.
+    puts "Copying site to gh-pages branch..."
     Dir.glob("site/*") do |path|
       next if path == "_site"
       sh "cp -R #{path} gh-pages/"
     end
 
-    # Commit the changes
+    # Commit and push.
+    puts "Committing and pushing to GitHub Pages..."
     sha = `git log`.match(/[a-z0-9]{40}/)[0]
-    sh "cd gh-pages && git add . && git commit -m 'Updating to #{sha}.' && git push"
+    Dir.chdir('gh-pages') do
+      sh "git add ."
+      sh "git commit -m 'Updating to #{sha}.'"
+      sh "git push origin gh-pages"
+    end
     puts 'Done.'
   end
 end