here is what I suggest you could do

gistfile1.rb

require 'active_support/all'

class Article
  attr_accessor :id
 
  def initialize(attributes={})
    @id = attributes[:id]
  end
 
  
  def ==(comparison_object)
    super ||
      comparison_object.instance_of?(self.class) &&
      self.id.present? &&
      self.id == comparison_object.id
  end
  alias :eql? :==
end
 
 
a1 = Article.new(id: 1)
a2 = Article.new(id: 1)
a3 = Article.new(id: 1)
 
puts [a1, a2, a3].uniq_by {|a,b| a == b} #=> [#<Article ...>]