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: 20211213172901_create_saas_subscription.rb
    path of file: ./repos/ekylibre/db/migrate
    
    the code of the file until where you have to start completion: class CreateSaasSubscription < ActiveRecord::Migration[5.0]
  def change
    c
    
  def add_provider_to(table_name)
    if column_exists? table_name, :provider
      remove_column table_name, :provider, :jsonb
      add_column table_name, :provider, :jsonb, default: {}
    else
      add_column table_name, :provider, :jsonb, default: {}
    end