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: 20190805215030_create_monthly_auth_counts.rb
    path of file: ./repos/identity-idp/db/primary_migrate
    
    the code of the file until where you have to start completion: class CreateMonthlyAuthCounts < ActiveRecord::Migration[5.
    
  def change
    create_table :monthly_auth_counts do |t|
      t.string :issuer, null: false
      t.string :year_month, null: false
      t.integer :user_id, null: false
      t.integer :auth_count, default: 1, null: false
    end
    add_index :monthly_auth_counts, %i[issuer year_month user_id], algorithm: :concurrently, unique: true
  end