x.rb

module Person
  attr_accessor :email, :first_name, :last_name
end

class Employee
  include Person

  attr_accessor :role
end 

## Alternatively

class Person
  attr_accessor :email, :first_name, :last_name
end

class Employee
  def initialize(person)
    self.person = person
    self.role   = role
  end

  attr_accessor :person, :role
end