To create the table for todo table structure We have to run

rake acts_as_todo:create

to rollback

rake acts_as_todo:roll_back


To create the relation between models and Todo class

class Lesson < ActiveRecord::Base
  aatd
end

class User < ActiveRecord::Base
  work_to_do
end

This will show how the relation works



User.create(:name => 'tripurari')
 => #<User id: 1, name: "tripurari", created_at: "2011-06-03 04:49:31", updated_at: "2011-06-03 04:49:31"> 
Lesson.create(:name => "should be done")
 => #<Lesson id: 1, name: "should be done", created_at: "2011-06-03 04:50:04", updated_at: "2011-06-03 04:50:04"> 
Lesson.create(:name => "Should be done later")
 => #<Lesson id: 2, name: "Should be done later", created_at: "2011-06-03 04:50:23", updated_at: "2011-06-03 04:50:23"> 
User.first.todos.create(:work => Lesson.first)
 => #<Todo id: 1, worker_id: 1, worker_type: "User", work_id: 1, work_type: "Lesson", started_at: nil, end_at: nil, created_at: "2011-06-03 04:50:32", updated_at: "2011-06-03 04:50:32"> 
Lesson.last.todos.create(:worker => User.first)
 => #<Todo id: 2, worker_id: 1, worker_type: "User", work_id: 2, work_type: "Lesson", started_at: nil, end_at: nil, created_at: "2011-06-03 04:50:39", updated_at: "2011-06-03 04:50:39"> 
Todo.first.work
 => #<Lesson id: 1, name: "should be done", created_at: "2011-06-03 04:50:04", updated_at: "2011-06-03 04:50:04"> 
Todo.first.worker
 => #<User id: 1, name: "tripurari", created_at: "2011-06-03 04:49:31", updated_at: "2011-06-03 04:49:31">



Now We can change the states of a todo object

The available states we can find through this command

Todo.first.all_states will give

 => {:new=>[:start, :onhold], :start=>[:complete, :onhold], :complete=>[:restart], :onhold=>[:start, :complete], :restart=>[:start]} 

And all the states available for todo's are 

Todo.first.available_states
 => [:start, :complete] 

Whether the state change is valid or not

Todo.first.can_change_state?(:new)
 => false 

Change the status of todo

Todo.first.start
   (244.9ms)  BEGIN
   (187.4ms)  UPDATE `todos` SET `status` = 'start', `updated_at` = '2012-06-15 11:07:39' WHERE `todos`.`id` = 1
   (74.7ms)  COMMIT
 => true

When the state transition is not valid it will give an error

Todo.first.restart
 => ["State Cannot Changed from start to start. Available stated to change are [:complete, :onhold]"