Undefined method remember_me! for (my user class)

[mark100net]

I am using version 0.11.0 with Rails 5.1.4. I was not using remember_me originally and just started trying to use it.

My sorcery.rb has this:

Rails.application.config.sorcery.submodules = [:remember_me]
 ....

 config.user_class = "Person" #last line

My Person class this:

class Person < ApplicationRecord
     authenticates_with_sorcery!

My people table has remember_me_token and remember_me_token_expires_at

I try to create the session like so:

if @person && (@person = login(@person.email, params[:password], true)) <-- NoMethodError 
     redirect_back_or_to(admin_root_path, notice: "Login successful")

The error message is

undefined method `remember_me!' for #<Person:0x00000000049cff28>

Am I missing something?