assigned a user id, does not "appear" to have screwed anything up

app/models/user.rb

@@ -8,6 +8,9 @@ class User < ActiveRecord::Base
   validates_presence_of :email
   validates_uniqueness_of :email
   validates_format_of :email, :with => /.+@.+\..+/i
+  attr_accessor :skip_user_id_assign
+  before_save :assign_user_id, :on => :create
+ 
   
 
   def self.authenticate(email, password)
@@ -25,5 +28,13 @@ class User < ActiveRecord::Base
        end
        return auth
   end  
+  
+  def assign_user_id
+     unless @skip_user_id_assign.present?
+      user = User.order("user_id").last
+      uid = user.user_id.to_i + 1 if user && user.user_id && !(User.exists?(:user_id => "#{user.user_id.to_i + 1}"))
+      self.user_id = uid.to_s if uid
+     end
+  end
 
 end