Help with undefined method `default_scoping?' for Class

[maricavor]

Please help, I have two models, like Workout and Set, workout embeds_many sets:

class Workout
  include Mongoid::Document
  include Mongoid::Timestamps

  field :name, type: String
  field :date, type: Date
  field :notes, type: String
  field :planned_start_time, type: Integer
  field :planned_end_time, type: Integer
  field :actual_start_time, type: Integer
  field :actual_end_time, type: Integer
  field :public, type: Boolean, default: false

  belongs_to :user
  embeds_many :sets

  index({ user_id: 1 })
  index({ name: 1 })
end

class Set
  include Mongoid::Document
  include Mongoid::Timestamps

  field :planned_weight, type: Integer
  field :planned_reps, type: Integer
  field :planned_rest, type: Integer
  field :planned_intensity, type: Integer
  field :actual_weight, type: Integer
  field :actual_reps, type: Integer
  field :actual_rest, type: Integer
  field :actual_intensity, type: Integer
  # Omitting _id Field
  field :_id, type: Object

  embedded_in :workout
end

When I try to create a workout Workout.create(name: "Leg day"), I get error:
/usr/local/bundle/gems/mongoid-8.0.3/lib/mongoid/association/embedded/embeds_many/proxy.rb:476:in `scope': undefined method `default_scoping?' for Set:Class (NoMethodError)

Why class Set does not support methods like default_scoping? or order_by?

[maricavor]

Ok, I will answer by myself. Looks like Set is a reserved word in Rails, by changing Set class to WorkoutSet the error is gone!