add individual user preference read/write, and default all new users to having public data

db/migrate/012_add_user_preference_id.rb

@@ -0,0 +1,12 @@
+class AddUserPreferenceId < ActiveRecord::Migration
+  def self.up
+    add_column "user_preferences", "id", :bigint, :limit => 64, :null => false, :options => "AUTO_INCREMENT"
+    
+    add_index "user_preferences", ["id"], :name => "user_preferences_id_idx"
+  end
+
+  def self.down
+    remove_index 'user_preferences', 'id'
+    remove_column 'user_preferences', 'id'
+  end
+end