Updated app/models/question.rb.

Change:
  - For Question identifiers functionality.

Author: John Pinto

app/models/question.rb

@@ -53,6 +53,8 @@ class Question < ApplicationRecord
   # inverse_of needed for nested forms
   has_many :question_options, dependent: :destroy, inverse_of: :question
 
+  has_many :question_identifiers, dependent: :destroy
+
   has_many :annotations, dependent: :destroy, inverse_of: :question
 
   has_and_belongs_to_many :themes, join_table: 'questions_themes'
@@ -101,6 +103,8 @@ class Question < ApplicationRecord
 
   accepts_nested_attributes_for :question_options, allow_destroy: true,
                                                    reject_if: ->(a) { a[:text].blank? }
+  
+  accepts_nested_attributes_for :question_identifiers, allow_destroy: true
 
   accepts_nested_attributes_for :annotations, allow_destroy: true,
                                               reject_if: proc { |a| a[:text].blank? && a[:id].blank? }
@@ -121,6 +125,8 @@ def deep_copy(**options)
     copy.save!(validate: false) if options.fetch(:save, false)
     options[:question_id] = copy.id
     question_options.each { |qo| copy.question_options << qo.deep_copy(**options) }
+    # question_identifiers deep_copy bit
+    question_identifiers.each { |qi| copy.question_identifiers << qi.deep_copy(**options) }
     annotations.each do |annotation|
       copy.annotations << annotation.deep_copy(**options)
     end