obdev/app/models/participant.rb

class Participant < ApplicationRecord
  # Associations
  belongs_to :employer, optional: true
  has_many :employments
  has_many :workers, through: :employments
  has_many :service_contracts
  has_many :vendors, through: :service_contracts

  # Validations
  validates :first_name, presence: true
  validates :last_name, presence: true
  def full_name
    "#{first_name} #{last_name}"
  end

  # Other associations
  has_and_belongs_to_many :programs
end