fix dependency issue with how TokenMaster::Model module is added to A…

[francirp]

Resolves #47

Since we're using the on_load hook, self is actually the ApplicationRecord class (or ActiveRecord::Base for Rails 4), so there is no need to use the class name when including our module. Referencing ApplicationRecord was creating a circular dependency, though I'm not sure why.

Here is an article that explains it more: https://simonecarletti.com/blog/2011/04/understanding-ruby-and-rails-lazy-load-hooks/

[inveterateliterate]

That is really interesting that we didn't get an error earlier. I can't remember why we included it like this to begin with, but good find!

Other notes:

https://github.com/rails/rails/blob/v3.0.6/activesupport/lib/active_support/lazy_load_hooks.rb (I see then that since we're passing active_record to the block, it is the self)

https://blog.bigbinary.com/2015/12/28/application-record-in-rails-5.html (we didn't really need to separate rails 5 from non-rails 5 to begin with either)