You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: 20150713125423_create_assessments.rb
    path of file: ./repos/coursemology2/db/migrate
    
    the code of the file until where you have to start completion: # frozen_string_literal: true
class CreateAssessments < ActiveRecord::Migration[4.2]
  def change
    create_table :course_assessment_categories do |t|
      t.references :course, null: false
      t.string :title, null: false
      t.integer :weight, null: false

      t.userstamps null: false, foreign_key: { references: :users }
      t.timestamps null: false
    end

    create_table :course_assessment_tabs do |t|
      t.references :category, null: false,
                              foreign_key: { references: :course_assessment_categories }
      t.string :title, null: false
      t.integer :weig
    
  def change
    create_table :course_assessment_categories do |t|
      t.references :course, null: false
      t.string :title, null: false
      t.integer :weight, null: false

      t.userstamps null: false, foreign_key: { references: :users }
      t.timestamps null: false
    end

    create_table :course_assessment_tabs do |t|
      t.references :category, null: false,
                              foreign_key: { references: :course_assessment_categories }
      t.string :title, null: false
      t.integer :weight, null: false

      t.userstamps null: false, foreign_key: { references: :users }
      t.timestamps null: false
    end

    create_table :course_assessments do |t|
      t.references :tab, null: false,
                         foreign_key: { references: :course_assessment_tabs }

      t.userstamps null: false, foreign_key: { references: :users }
      t.timestamps null: false
    end

    create_table :course_assessment_tag_groups do |t|
      t.string :title, null: false
      t.text :description, null: false

      t.userstamps null: false, foreign_key: { references: :users }
      t.timestamps null: false
    end

    create_table :course_assessment_tags do |t|
      t.references :tag_group, foreign_key: { references: :course_assessment_tag_groups }
      t.string :title, null: false
      t.text :description, null: false

      t.userstamps null: false, foreign_key: { references: :users }
      t.timestamps null: false
    end

    create_table :course_assessment_questions do |t|
      t.actable index: { unique: true, name: :index_course_assessment_questions_actable }
      t.references :assessment, null: false, foreign_key: { references: :course_assessments }
      t.text :description, null: false

      t.userstamps null: false, foreign_key: { references: :users }
      t.timestamps null: false
    end

    create_table :course_assessment_questions_tags do |t|
      t.references :question, foreign_key: { references: :course_assessment_questions },
                              index: { name: :course_assessment_question_tags_question_index }
      t.references :tag, foreign_key: { references: :course_assessment_tags },
                         index: { name: :course_assessment_question_tags_tag_index }
    end

    create_table :course_assessment_submissions do |t|
      t.references :assessment, null: false, foreign_key: { references: :course_assessments }
      t.references :course_user, null: false, foreign_key: { references: :course_users }

      t.userstamps null: false, foreign_key: { references: :users }
      t.timestamps null: false
    end

    create_table :course_assessment_answers do |t|
      t.actable index: { unique: true, name: :index_course_assessment_answers_actable }
      t.references :submission, null: false,
                                foreign_key: { references: :course_assessment_submissions }
      t.references :question, null: false,
                              foreign_key: { references: :course_assessment_questions }
    end
  end