add usage/help to resource command

git-svn-id: file:///home/svn/framework3/trunk@6101 4d416f70-5f16-0410-b530-b9f4589650da

lib/msf/ui/console/command_dispatcher/core.rb

@@ -107,6 +107,12 @@ class Core
 	end
 
 	def cmd_resource(*args)
+		if args.empty?
+			print(
+				"Usage: resource <path>\n\n" +
+				"Run the commands stored in the supplied file.\n")
+			return false
+		end
 		driver.load_resource(*args)
 	end