Skal jeg slette standard-id-feltet, når jeg bruger en streng primærnøgle i Rails / Postgres?

Ifølge dette post, burde det løse problemet:

class CreateEmployees < ActiveRecord::Migration
  def change
    create_table :employees, {:id => false} do |t|
      t.string :employment_id, :unique => true
      etc...
    end
  end
  execute "ALTER TABLE employees ADD PRIMARY KEY (employment_id);"
end

Også i din model:

class Employee < ActiveRecord::Base
  set_primary_key :employment_id
  ...
end