Adding a custom seed file

Start by creating a separate directory to hold your custom seeds – this example uses db/seeds. Then, create a custom task by adding a rakefile to your lib/tasks directory:

# lib/tasks/custom_seed.rake
namespace :db do
  namespace :seed do
    Dir[Rails.root.join('db', 'seeds', '*.rb')].each do |filename|
      task_name = File.basename(filename, '.rb')
      desc "Seed " + task_name + ", based on the file with the same name in `db/seeds/*.rb`"
      task task_name.to_sym => :environment do
        load(filename) if File.exist?(filename)
      end
    end
  end
end

This rakefile accepts the name of a seed file in the db/seeds directory (excluding the .rb extension), then runs it as it would run seeds.rb. You can execute the rake task by issuing the following from the command line:

rake db:seed:file_name # Name of the file EXCLUDING the .rb extension 

Update: Now it should also list the seed tasks when running rake --tasks or rake -T.