<NameError: uninitialized constant #<Class:0x0000557d7c986aa8>::Report>

Loading development environment (Rails 5.2.0)
irb(main):001:0> RUBY_VERSION
=> "2.3.6"

Loading production environment (Rails 5.2.0)
irb(main):001:0> RUBY_VERSION
=> "2.3.6"

#<NameError: uninitialized constant #<Class:0x0000557d7c986aa8>::Report>
/app/app/models/cart.rb:26:in `add_product'
/app/app/controllers/cart_controller.rb:10:in `add_remove'
/app/vendor/bundle/ruby/2.3.0/gems/actionpack-5.2.0/lib/action_controller/metal/basic_implicit_render.rb:6:in `send_action'

ruby '2.3.6'