I have successfully been able to implement the addition of new artist entries which was not included in Ryan Bates railscast #258 http://railscasts.com/episodes/258-token-fi
if you're using some authentication solution like devise, clearance or authlogic, you probably already have current_user method. Therefore add a column user_id:integer to the Artist model and do the following:
#User model
has_many :artists
#Artist model
belongs_to :user
#Artists controller
def index
@artists = current_user.artists.where("name like ?", "%#{params[:q]}%") #this answers your question!
... blah blah
end
And of course do not forget to set the user_id column when you create an artist.