Updated doc.

limmutable.c

@@ -4,11 +4,13 @@
 * that can be used to declare immutable classes, like so:
 *
 *     immutable = require 'immutable'
-*     local Foo = immutable({"baz","qux"})
+*     local Foo = immutable({"baz","qux"}, {class_var=5})
 *     local foo = Foo("hello", 99)
+*     assert(foo.baz == "hello")
 *     assert(not pcall(function() foo.x = 'mutable' end))
 *     local t = {[foo]="it works"}
 *     assert(t[Foo("hello", 99)] == "it works")
+*     assert(foo.class_var == 5)
 * 
 * Instances *are* garbage collected.
 */