According to \"Custom Rake Tasks\":
desc \"Pick a random user as the winner\"
task :winner => :environment do
puts \"Winner: #{pick(User).name}\"
end
>
Including => :environment will tell Rake to load full the application environment, giving the relevant task access to things like classes, helpers, etc. Without the :environment, you won't have access to any of those extras.
Also => :environment itself does not make available any environment-related variables, e.g. environment, @environment, RAILS_ENV, etc.