> I initialize it and it worked ... but when can I use the
> attr_reader as a
> short cut

attr_reader, attr_writer, and attr_accessor are shortcuts for creating
getter/setter methods, not shortcuts for the constructor.

attr_reader :name1    is a shortcut for
def name1
   @name1
end

attr_writer :name1    is a shortcut for
def name1=(name)
   @name1 = name
end

attr_accessor :name1  will create both of those methods.

The idiom that most folk use for the initialize method is something like
this:

class SomeClass
  attr_reader :name1, :name2

  def initialize(name1, name2)
    @name1, @name2 = name1, name2
  end
end


Hope this clears things up,
aaron