Very naughty mega-commit. Added enum and validator specs. Everything seems to be working as expected

lib/mongoid/enum.rb

@@ -1,7 +1,41 @@
 require "mongoid/enum/version"
+require "mongoid/enum/validators/multiple_validator"
 
 module Mongoid
   module Enum
-    # Your code goes here...
+    extend ActiveSupport::Concern
+    module ClassMethods
+      def enum(name, values, options = {})
+        field_name = :"_#{name}"
+        const_name = name.to_s.upcase
+        multiple = options[:multiple] || false
+        default = options[:default].nil? && values.first || options[:default]
+        required = options[:required].nil? || options[:required]
+
+        const_set const_name, values
+
+        type = multiple && Array || Symbol
+        field field_name, :type => type, :default => default
+        alias_attribute name, field_name
+
+        if multiple
+          validates field_name, :'mongoid/enum/validators/multiple' => { :in => values, :allow_nil => !required }
+        else
+          validates field_name, :inclusion => {:in => values}, :allow_nil => !required
+        end
+
+        values.each do |value|
+          scope value, where(field_name => value)
+
+          if multiple
+            class_eval "def #{value}?() self.#{field_name}.include?(:#{value}) end"
+            class_eval "def #{value}!() update_attributes! :#{field_name} => (self.#{field_name} || []) + [:#{value}] end"
+          else
+            class_eval "def #{value}?() self.#{field_name} == :#{value} end"
+            class_eval "def #{value}!() update_attributes! :#{field_name} => :#{value} end"
+          end
+        end
+      end
+    end
   end
 end