ruby script/plugin install http://svn.baconbear.com/rails_plugins/acts_as_flaggable/trunk

Create a new rails migration and add the following self.up and self.down methods

 def self.up
   create_table :flags, :force => true do |t|
     t.column :flag, :string, :default => ""
     t.column :comment, :string, :default => ""
     t.column :created_at, :datetime, :null => false
     t.column :flaggable_id, :integer, :default => 0, :null => false
     t.column :flaggable_type, :string, :limit => 15,
       :default => "", :null => false
     t.column :user_id, :integer, :default => 0, :null => false
   end

   add_index :flags, ["user_id"], :name => "fk_flags_user"
 end

 def self.down
   drop_table :flags
 end

Make you ActiveRecord model act as flaggable.

 class Model < ActiveRecord::Base
 	acts_as_flaggable
 end

Add a flag to a model instance

 model = Model.new
 flag = Flag.new
 flag.flag = 'Some flag'
 model.flags.add_flag flag

When a flag is added via add_flag, flagged(flag, flag_count) is called on the flaggable model. This allows the model to perform certain operations if the number of flags reaches a certain point. For example, you may want to mark a Post as deleted if a Post receives too many "spam" flags

Each flag reference flaggable object

 model = Model.find(1)
 model.flags.get(0).commtable == model

There is currently no advanced documentation for this plugin.