Set primary_key

app/models/employee.rb

@@ -13,6 +13,8 @@ class Employee < ActiveRecord::Base
   has_many :users
   validates_presence_of :id, :name
 
+  self.primary_key = :id
+
   # Sync all employees, typically triggered by a scheduled task or manual sync request
   def self.sync
     EmployeeSyncJob.perform_later(full_sync: true)