obdev/app/models/vendor.rb

class Vendor < ApplicationRecord
  # Many-to-many relationships
  has_and_belongs_to_many :employers
  has_many :service_contracts
  has_many :participants, through: :service_contracts
  has_many :bank_accounts, as: :owner
  has_many :onboarding_items, as: :owner
  accepts_nested_attributes_for :onboarding_items

  # Validations
  validates :tin, uniqueness: true, allow_blank: true, presence: true
end