gem install rails -v 3.2.22.5

rails _3.2.22.5_ new test_seed_fu
cd test_seed_fu

cat << EOS >> Gemfile
group :development do
  gem 'seed-fu', '2.3.6'
end
EOS

bundle install

script/rails g model User name:string age:integer
bundle exec rake db:migrate

mkdir -p db/fixtures/development
cat << EOS > db/fixtures/development/users.rb
User.seed(:name) do |u|
  u.name = 'User Name'
  u.age = 20
end
EOS

bundle exec rake db:seed_fu
# => rake aborted! ArgumentError: wrong number of arguments (given 0, expected 1) ...

script/rails r "User.seed(:name, name: 'User Name', age: 20)"
# => wrong number of arguments (given 0, expected 1) (ArgumentError) ..