has_many :through question

I am trying to create an association table using the ":through" option
in "has_many" but not having success. I have created the necessary
migrations of the association tables and run rake db:migrate

I have the following model:

class Group < ActiveRecord::Base
  has_many :users, :through => :group_user
  has_many :invites, :through => :group_invite, :class_name => "User"
  belongs_to :owner, :class_name => "User"
end

class GroupUser < ActiveRecord::Base
  belongs_to :group
  belongs_to :user
end

Loading development environment (Rails 2.3.8)

g = Group.find(1)

=> #<Group id: 1, name: "My Group", owner_id: 1, created_at: "2010-08-19
02:30:10", updated_at: "\
2010-08-19 02:30:10">

g.users << User.find(2)

ActiveRecord::HasManyThroughAssociationNotFoundError: Could not find the
association :group_user \
in model Group
        from
/usr/local/lib/ruby/gems/1.8/gems/activerecord-2.3.8/lib/active_record/reflection.rb\
:348:in `check_validity!'
        from
/usr/local/lib/ruby/gems/1.8/gems/activerecord-2.3.8/lib/active_record/associations/\
association_proxy.rb:56:in `initialize'
        from
/usr/local/lib/ruby/gems/1.8/gems/activerecord-2.3.8/lib/active_record/associations/\
association_collection.rb:20:in `initialize'
        from
/usr/local/lib/ruby/gems/1.8/gems/activerecord-2.3.8/lib/active_record/associations.\
rb:1306:in `new'
        from
/usr/local/lib/ruby/gems/1.8/gems/activerecord-2.3.8/lib/active_record/associations.\
rb:1306:in `users'
        from (irb):2

Disregard, solution found.