rails relationship model

20180226225426_create_cats.rb

class CreateCats < ActiveRecord::Migration[5.0]
  def change
    create_table :cats do |t|
      t.string :name

      t.timestamps
    end
  end
end

20180502234327_cat_relationship.rb

class CatRelationship < ActiveRecord::Migration[5.0]
  def change
    create_table :cat_relationships do |t|
      t.references :giver, references: :cat, foreign_key: true
      t.references :taker, references: :cat, foreign_key: true
    end
  end
end

cat_relationship.rb

class CatRelationship < ApplicationRecord
  def self.relationship_exists?(giver:, taker:)
    where(giver_id: giver, taker_id: taker).exists?
  end
end

shell.rb

irb(main):001:0> ezzie = Cat.create(name: 'ezzie'); beans = Cat.create!(name: 'beans')
=> #<Cat id: 4, name: "beans", created_at: "2018-05-03 00:09:35", updated_at: "2018-05-03 00:09:35">
irb(main):002:0> CatRelationship.create!(giver_id: ezzie.id, taker_id: beans.id)
=> #<CatRelationship id: 3, giver_id: 3, taker_id: 4>
irb(main):003:0> CatRelationship.relationship_exists?(giver: ezzie, taker: beans)
  CatRelationship Exists (0.3ms)  SELECT  1 AS one FROM "cat_relationships" WHERE "cat_relationships"."giver_id" = 3 AND "cat_relationships"."taker_id" = 4 LIMIT ?  [["LIMIT", 1]]
=> true