Offerings

offerings.rb

# migration
class CreateOfferings < ActiveRecord::Migration[6.0]
  def change
    create_table :offerings do |t|
      t.references :product, foreign_key: true
      t.references :vendor, foreign_key: true
      # add other unique-to-vendor fields/associations

      t.timestamps
    end
  end
end

# offering model
class Offering < ApplicationRecord
  belongs_to :product
  belongs_to :vendor
end

# product model
class Product < ApplicationRecord
  has_many :offerings, dependent: :destroy
  has_many :vendors, through: :offerings
end

# vendor model
class Vendor < ApplicationRecord
  has_many :offerings, dependent: :destroy
  has_many :products, through: :offerings
end