diff --git a/app/models/post.rb b/app/models/post.rb
index 2276e1f1c..1d286c2e0 100644
--- a/app/models/post.rb
+++ b/app/models/post.rb
@@ -1,12 +1,10 @@
+require 'danbooru/has_bit_flags'
+
 class Post < ActiveRecord::Base
   class ApprovalError < Exception ; end
   class DisapprovalError < Exception ; end
   class SearchError < Exception ; end
 
-  BOOLEAN_ATTRIBUTES = {
-    :has_embedded_notes => 0x0001
-  }
-
   attr_accessor :old_tag_string, :old_parent_id, :old_source, :old_rating, :has_constraints, :disable_versioning, :view_count
   after_destroy :delete_files
   after_destroy :delete_remote_files
@@ -1597,24 +1595,12 @@ class Post < ActiveRecord::Base
   extend SearchMethods
   include PixivMethods
   include IqdbMethods
+  include Danbooru::HasBitFlags
 
-  BOOLEAN_ATTRIBUTES.each do |boolean_attribute, bit_flag|
-    define_method(boolean_attribute) do
-      bit_flags & bit_flag > 0
-    end
-
-    define_method("#{boolean_attribute}?") do
-      bit_flags & bit_flag > 0
-    end
-
-    define_method("#{boolean_attribute}=") do |val|
-      if val.to_s =~ /t|1|y/
-        self.bit_flags |= bit_flag
-      else
-        self.bit_flags &= ~bit_flag
-      end
-    end
-  end
+  BOOLEAN_ATTRIBUTES = %w(
+    has_embedded_notes
+  )
+  has_bit_flags BOOLEAN_ATTRIBUTES
 
   def visible?
     return false if !Danbooru.config.can_user_see_post?(CurrentUser.user, self)
diff --git a/app/models/user.rb b/app/models/user.rb
index 7cc71a827..dcba0b15c 100644
--- a/app/models/user.rb
+++ b/app/models/user.rb
@@ -1,4 +1,5 @@
 require 'digest/sha1'
+require 'danbooru/has_bit_flags'
 
 class User < ActiveRecord::Base
   class Error < Exception ; end
@@ -16,25 +17,25 @@ class User < ActiveRecord::Base
     ADMIN = 50
   end
 
+  BOOLEAN_ATTRIBUTES = %w(
+    is_banned
+    has_mail
+    receive_email_notifications
+    always_resize_images
+    enable_post_navigation
+    new_post_navigation_layout
+    enable_privacy_mode
+    enable_sequential_post_navigation
+    hide_deleted_posts
+    style_usernames
+    enable_auto_complete
+    show_deleted_children
+    has_saved_searches
+    can_approve_posts
+  )
 
-  # bit_prefs is 64 bits signed so theoretical maximum 
-  # is 0x8000 0000 0000 0000
-  BOOLEAN_ATTRIBUTES = {
-    :is_banned                         => 0x0001,
-    :has_mail                          => 0x0002,
-    :receive_email_notifications       => 0x0004,
-    :always_resize_images              => 0x0008,
-    :enable_post_navigation            => 0x0010,
-    :new_post_navigation_layout        => 0x0020,
-    :enable_privacy_mode               => 0x0040,
-    :enable_sequential_post_navigation => 0x0080,
-    :hide_deleted_posts                => 0x0100,
-    :style_usernames                   => 0x0200,
-    :enable_auto_complete              => 0x0400,
-    :show_deleted_children             => 0x0800,
-    :has_saved_searches                => 0x1000,
-    :can_approve_posts                 => 0x2000
-  }
+  include Danbooru::HasBitFlags
+  has_bit_flags BOOLEAN_ATTRIBUTES, :field => "bit_prefs"
 
   attr_accessor :password, :old_password
   attr_accessible :dmail_filter_attributes, :enable_privacy_mode, :enable_post_navigation, :new_post_navigation_layout, :password, :old_password, :password_confirmation, :password_hash, :email, :last_logged_in_at, :last_forum_read_at, :has_mail, :receive_email_notifications, :comment_threshold, :always_resize_images, :favorite_tags, :blacklisted_tags, :name, :ip_addr, :time_zone, :default_image_size, :enable_sequential_post_navigation, :per_page, :hide_deleted_posts, :style_usernames, :enable_auto_complete, :custom_style, :show_deleted_children, :as => [:moderator, :janitor, :contributor, :gold, :member, :anonymous, :default, :builder, :admin]
@@ -774,24 +775,6 @@ class User < ActiveRecord::Base
   include CountMethods
   extend SearchMethods
 
-  BOOLEAN_ATTRIBUTES.each do |boolean_attribute, bit_flag|
-    define_method(boolean_attribute) do
-      bit_prefs & bit_flag > 0
-    end
-
-    define_method("#{boolean_attribute}?") do
-      bit_prefs & bit_flag > 0
-    end
-
-    define_method("#{boolean_attribute}=") do |val|
-      if val.to_s =~ /t|1|y/
-        self.bit_prefs |= bit_flag
-      else
-        self.bit_prefs &= ~bit_flag
-      end
-    end
-  end
-
   def initialize_default_image_size
     self.default_image_size = "large"
   end
diff --git a/lib/danbooru/has_bit_flags.rb b/lib/danbooru/has_bit_flags.rb
new file mode 100644
index 000000000..7e66d5eb5
--- /dev/null
+++ b/lib/danbooru/has_bit_flags.rb
@@ -0,0 +1,33 @@
+module Danbooru
+  module HasBitFlags
+    extend ActiveSupport::Concern
+
+    module ClassMethods
+      # NOTE: the ordering of attributes has to be fixed#
+      # new attributes should be appended to the end.
+      def has_bit_flags(attributes, options = {})
+        field = options[:field] || :bit_flags
+
+        attributes.each.with_index do |attribute, i|
+          bit_flag = 1 << i
+
+          define_method(attribute) do
+            send(field) & bit_flag > 0
+          end
+
+          define_method("#{attribute}?") do
+            send(field) & bit_flag > 0
+          end
+
+          define_method("#{attribute}=") do |val|
+            if val.to_s =~ /t|1|y/
+              send("#{field}=", send(field) | bit_flag)
+            else
+              send("#{field}=", send(field) & ~bit_flag)
+            end
+          end
+        end
+      end
+    end
+  end
+end
\ No newline at end of file