Gist stack trace: https://gist.github.com/washu/df25072fdcc53af6bf58

Model
class Lecture

1. We store in our own collection instead of inheriting
   include Mongoid::Document
   include Mongoid::Timestamps
2. name of lecture/class
   field :name, type: String, default: ''

1. description of the class
   field :description, type: String, default: ''

1. who owns this class/lecture (customers can have thier own class/lecture)
   field :customer, type: String, default: Aztec::AZTEC

1. Pre test required for class
   field :require_pre_test, type: Boolean, default: false

1. enable pre test on/off
   field :enable_pre_test, type: Boolean, default: true

1. enable practice test
   field :enable_practice_test, type: Boolean, default: false

1. enable practice test
   field :enable_essay_test, type: Boolean, default: false

embeds_one :pre_test_config, class_name: 'AutomaticTest', inverse_of: :testable
embeds_one :post_test_config, class_name: 'AutomaticTest', inverse_of: :testable

1. use customer or automatic tests
   embeds_one :pre_test_custom, class_name: 'ManualTest', inverse_of: :testable
   embeds_one :post_test_custom, class_name: 'ManualTest', inverse_of: :testable

1. Practice Test is always manula
   embeds_one :practice_test, class_name: 'ManualTest', inverse_of: :testable

1. Essay Test
   embeds_one :essay_test, class_name: 'ManualTest', inverse_of: :testable

1. test types
   field :manual_pre_test, type: Boolean, default: false
   field :manual_post_test, type: Boolean, default: false

1. enable drilling
   field :enable_drill, type: Boolean, default: true

1. unit of content
   has_and_belongs_to_many :units, index: true

1. Licenses
   has_and_belongs_to_many :license, index: true
   end
   class AutomaticTest
   include Mongoid::Document
   include Mongoid::Attributes::Dynamic
2. number of questions per problem sets available
   field :number_of_questions, type: Integer, default: 1
3. percentage score of the test
   field :passing_score, type: Integer, default: 80
4. enable timer
   field :enable_timer, type: Boolean, default: false
5. total time allow for test in minutes
   field :test_time, type: Integer, default: 60
6. Points per question
   field :points_per_question, type: Integer, default: 1
   field :allow_essay, type: Boolean, default: false

1. Do we need a calculator?
   field :calculator, type: Boolean, default: false
2. What calculator do we need
   field :calculator_type, type: String, default: 'GED'
   end
   class ManualTest < AutomaticTest
3. problems sets to use
   field :problem_set_id, type: BSON::ObjectId
4. random support
   field :randomize, type: Boolean
   embedded_in :testable , polymorphic: true
   end