Trying to run Purugin with Craftbukkit 1.3.1

gistfile1.txt

195 recipes
27 achievements
15:18:38 [INFO] Starting minecraft server version 1.3.1
15:18:38 [INFO] Loading properties
15:18:38 [INFO] Default game type: SURVIVAL
15:18:38 [INFO] Generating keypair
15:18:38 [INFO] Starting Minecraft server on *:25565
15:18:38 [INFO] This server is running CraftBukkit version git-Bukkit-1.3.1-R1.0-b2320jnks (MC: 1.3.1) (Implementing API version 1.3.1-R1.0)
15:18:38 [SEVERE] Could not load 'plugins/Purugin.jar' in folder 'plugins'
org.bukkit.plugin.InvalidPluginException: java.lang.NoClassDefFoundError: org/jruby/embed/ScriptingContainer
	at org.bukkit.plugin.java.JavaPluginLoader.loadPlugin(JavaPluginLoader.java:153)
	at org.bukkit.plugin.SimplePluginManager.loadPlugin(SimplePluginManager.java:305)
	at org.bukkit.plugin.SimplePluginManager.loadPlugins(SimplePluginManager.java:230)
	at org.bukkit.craftbukkit.CraftServer.loadPlugins(CraftServer.java:222)
	at org.bukkit.craftbukkit.CraftServer.<init>(CraftServer.java:198)
	at net.minecraft.server.ServerConfigurationManagerAbstract.<init>(ServerConfigurationManagerAbstract.java:50)
	at net.minecraft.server.ServerConfigurationManager.<init>(SourceFile:11)
	at net.minecraft.server.DedicatedServer.init(DedicatedServer.java:105)
	at net.minecraft.server.MinecraftServer.run(MinecraftServer.java:380)
	at net.minecraft.server.ThreadServerApplication.run(SourceFile:539)
Caused by: java.lang.NoClassDefFoundError: org/jruby/embed/ScriptingContainer
	at org.purugin.PuruginPlugin.<init>(PuruginPlugin.java:16)
	at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
	at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:39)
	at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:27)
	at java.lang.reflect.Constructor.newInstance(Constructor.java:513)
	at org.bukkit.plugin.java.JavaPluginLoader.loadPlugin(JavaPluginLoader.java:149)
	... 9 more
Caused by: java.lang.ClassNotFoundException: org.jruby.embed.ScriptingContainer
	at java.net.URLClassLoader$1.run(URLClassLoader.java:202)
	at java.security.AccessController.doPrivileged(Native Method)
	at java.net.URLClassLoader.findClass(URLClassLoader.java:190)
	at org.bukkit.plugin.java.PluginClassLoader.findClass(PluginClassLoader.java:41)
	at org.bukkit.plugin.java.PluginClassLoader.findClass(PluginClassLoader.java:29)
	at java.lang.ClassLoader.loadClass(ClassLoader.java:306)
	at java.lang.ClassLoader.loadClass(ClassLoader.java:247)
	... 15 more
15:18:39 [INFO] Preparing level "world"
15:18:39 [INFO] Placed stronghold in INVALID biome at (-11, -64)
15:18:39 [INFO] Preparing start region for level 0 (Seed: -5681965993303250424)
15:18:40 [INFO] Stopping server