Add a basic hudson install formula & plist startup

Startup logic by Jérôme Renard:
http://jrenard.info/blog/a-quick-but-working-startup-item-for-hudson-for-mac-os-x.html

Signed-off-by: Tim Shadel <github@timshadel.com>
Signed-off-by: Mike McQuaid <mike@mikemcquaid.com>

Formula/hudson.rb

@@ -0,0 +1,50 @@
+require 'formula'
+
+class Hudson <Formula
+  url 'http://hudson-ci.org/download/war/1.389/hudson.war', :using => :nounzip
+  version '1.389'
+  md5 'db6b12c5e6ac94e7cbd2e8f4334c368c'
+  homepage 'http://hudson-ci.org'
+
+  def install
+    lib.install "hudson.war"
+    (prefix+'org.hudson-ci.plist').write startup_plist
+  end
+
+  def caveats; <<-EOS
+If this is your first install, automatically load on login with:
+    cp #{prefix}/org.hudson-ci.plist ~/Library/LaunchAgents
+    launchctl load -w ~/Library/LaunchAgents/org.hudson-ci.plist
+
+If this is an upgrade and you already have the org.hudson-ci.plist loaded:
+    launchctl unload -w ~/Library/LaunchAgents/org.hudson-ci.plist
+    cp #{prefix}/org.hudson-ci.plist ~/Library/LaunchAgents
+    launchctl load -w ~/Library/LaunchAgents/org.hudson-ci.plist
+
+Or start it manually:
+    java -jar #{lib}/hudson.war
+EOS
+  end
+
+  def startup_plist
+    return <<-EOS
+<?xml version="1.0" encoding="UTF-8"?>
+<!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
+<plist version="1.0">
+<dict>
+    <key>Label</key>
+    <string>Hudson</string>
+    <key>ProgramArguments</key>
+    <array>
+    <string>/usr/bin/java</string>
+    <string>-jar</string>
+    <string>#{lib}/hudson.war</string>
+    </array>
+    <key>RunAtLoad</key>
+    <true/>
+</dict>
+</plist>
+EOS
+  end
+
+end