resque を使用する単純な ruby (非レール) アプリがあり、heroku で config.ru がないと起動しません。config.ru ファイルを追加すると、rackupローカルで実行すると次のエラーが発生します。
/usr/local/Cellar/ruby/1.9.3-p194/lib/ruby/gems/1.9.1/gems/rack-1.5.2/lib/rack/builder.rb:133:in `to_app': missing run or map statement (RuntimeError)
from /Users/nickkarrasch/Dropbox/Coding/Ruby/smsnotifyv2/config.ru:in `<main>'
from /usr/local/Cellar/ruby/1.9.3-p194/lib/ruby/gems/1.9.1/gems/rack-1.5.2/lib/rack/builder.rb:49:in `eval'
from /usr/local/Cellar/ruby/1.9.3-p194/lib/ruby/gems/1.9.1/gems/rack-1.5.2/lib/rack/builder.rb:49:in `new_from_string'
from /usr/local/Cellar/ruby/1.9.3-p194/lib/ruby/gems/1.9.1/gems/rack-1.5.2/lib/rack/builder.rb:40:in `parse_file'
from /usr/local/Cellar/ruby/1.9.3-p194/lib/ruby/gems/1.9.1/gems/rack-1.5.2/lib/rack/server.rb:277:in `build_app_and_options_from_config'
from /usr/local/Cellar/ruby/1.9.3-p194/lib/ruby/gems/1.9.1/gems/rack-1.5.2/lib/rack/server.rb:199:in `app'
from /usr/local/Cellar/ruby/1.9.3-p194/lib/ruby/gems/1.9.1/gems/rack-1.5.2/lib/rack/server.rb:314:in `wrapped_app'
from /usr/local/Cellar/ruby/1.9.3-p194/lib/ruby/gems/1.9.1/gems/rack-1.5.2/lib/rack/server.rb:250:in `start'
from /usr/local/Cellar/ruby/1.9.3-p194/lib/ruby/gems/1.9.1/gems/rack-1.5.2/lib/rack/server.rb:141:in `start'
from /usr/local/Cellar/ruby/1.9.3-p194/lib/ruby/gems/1.9.1/gems/rack-1.5.2/bin/rackup:4:in `<top (required)>'
from /usr/local/Cellar/ruby/1.9.3-p194/bin/rackup:23:in `load'
from /usr/local/Cellar/ruby/1.9.3-p194/bin/rackup:23:in `<main>'
config.ru には何を入れる必要がありますか?