Special password validation for devise

gistfile1.rb

class AdminToolUser < ActiveRecord::Base
  # Setup accessible (or protected) attributes for the model
  attr_accessible :email, :password, :password_confirmation, :remember_me, :first_name, :last_name
  
  validates_presence_of :first_name, :last_name
  
  # Include default devise modules. Others available are:
  # :token_authenticatable, :confirmable, :registerable, :lockable and :timeoutable
  devise :database_authenticatable, :recoverable, :rememberable, :trackable
  
  validate :password_must_exist, :password_must_match, :password_length, :if => :password_required?
  
  protected
  def password_required?
    !persisted? || (password.present? && password_confirmation.present?)
  end
  def password_must_exist
    errors.add(:password, "can't be blank") if password.blank?
  end
 
  def password_must_match
    errors.add(:password, "doesn't match confirmation") if password != password_confirmation
  end
  def password_length
    errors.add(:password, "must be at least 6 characters long (and less than 30)") if (password.split(//).size < 6 || password.split(//).size > 29)
  end
end