def seed_once(*args, &block)
      constraints, data = parse_seed_fu_args(args, block)
      SeedFu::Seeder.new(self, constraints, data, :insert_only => true).seed
    end
def seed_once(*args, &block)
      constraints, data = parse_seed_fu_args(args, block)
      SeedFu::Seeder.new(self, constraints, data, :insert_only => true).seed
    end
Has the same syntax as {#seed}, but if a record already exists with the same values for
 constraining attributes, it will not be updated.

 @example
   Person.seed(:id, :id => 1, :name => "Jon") # => Record created
   Person.seed(:id, :id => 1, :name => "Bob") # => Name changed
   Person.seed_once(:id, :id => 1, :name => "Harry") # => Name *not* changed