delay the removal of auth token column from user table

db/migrate/20170124181409_add_user_auth_tokens.rb

@@ -1,7 +1,5 @@
 class AddUserAuthTokens < ActiveRecord::Migration
   def down
-    add_column :users, :auth_token, :string
-    add_column :users, :auth_token_updated_at, :datetime
     execute <<SQL
       UPDATE users
         SET auth_token = user_auth_tokens.auth_token,
@@ -36,8 +34,5 @@ SQL
     FROM users
     WHERE auth_token_updated_at IS NOT NULL AND auth_token IS NOT NULL
 SQL
-
-    remove_column :users, :auth_token
-    remove_column :users, :auth_token_updated_at
   end
 end