title: Error Adding a Migration: `default_controller_and_action': missing :action (ArgumentError)
body: <p>I'm trying add the following migration:</p>
  
  <pre><code>rails g migration AddConfirmableToUsers confirmation_token:string confirmed_at:datetime confirmation_sent_at:datetime unconfirmed_email:string
  </code></pre>
  
  <p>However, it raised the following error I'm unable to troubleshoot:</p>
  
  <pre><code>/Users/tn/.rvm/gems/ruby-2.0.0-rc1@global/gems/actionpack-3.2.13/lib/action_dispatch/routing/mapper.rb:179:in `default_controller_and_action': missing :action (ArgumentError)
      from /Users/tn/.rvm/gems/ruby-2.0.0-rc1@global/gems/actionpack-3.2.13/lib/action_dispatch/routing/mapper.rb:72:in `normalize_options!'
      from /Users/tn/.rvm/gems/ruby-2.0.0-rc1@global/gems/actionpack-3.2.13/lib/action_dispatch/routing/mapper.rb:60:in `initialize'
      from /Users/tn/.rvm/gems/ruby-2.0.0-rc1@global/gems/actionpack-3.2.13/lib/action_dispatch/routing/mapper.rb:1308:in `new'
      from /Users/tn/.rvm/gems/ruby-2.0.0-rc1@global/gems/actionpack-3.2.13/lib/action_dispatch/routing/mapper.rb:1308:in `add_route'
      from /Users/tn/.rvm/gems/ruby-2.0.0-rc1@global/gems/actionpack-3.2.13/lib/action_dispatch/routing/mapper.rb:1287:in `decomposed_match'
      from /Users/tn/.rvm/gems/ruby-2.0.0-rc1@global/gems/actionpack-3.2.13/lib/action_dispatch/routing/mapper.rb:1269:in `block in match'
      from /Users/tn/.rvm/gems/ruby-2.0.0-rc1@global/gems/actionpack-3.2.13/lib/action_dispatch/routing/mapper.rb:1269:in `each'
      from /Users/tn/.rvm/gems/ruby-2.0.0-rc1@global/gems/actionpack-3.2.13/lib/action_dispatch/routing/mapper.rb:1269:in `match'
      from /Users/tn/.rvm/gems/ruby-2.0.0-rc1@global/gems/actionpack-3.2.13/lib/action_dispatch/routing/mapper.rb:254:in `root'
      from /Users/tn/.rvm/gems/ruby-2.0.0-rc1@global/gems/actionpack-3.2.13/lib/action_dispatch/routing/mapper.rb:1321:in `root'
      from /Users/tn/rails_projects/rails-prelaunch-signup/config/routes.rb:5:in `block in &lt;top (required)&gt;'
      from /Users/tn/.rvm/gems/ruby-2.0.0-rc1@global/gems/actionpack-3.2.13/lib/action_dispatch/routing/route_set.rb:289:in `instance_exec'
      from /Users/tn/.rvm/gems/ruby-2.0.0-rc1@global/gems/actionpack-3.2.13/lib/action_dispatch/routing/route_set.rb:289:in `eval_block'
      from /Users/tn/.rvm/gems/ruby-2.0.0-rc1@global/gems/actionpack-3.2.13/lib/action_dispatch/routing/route_set.rb:267:in `draw'
      from /Users/tn/rails_projects/rails-prelaunch-signup/config/routes.rb:1:in `&lt;top (required)&gt;'
      from /Users/tn/.rvm/gems/ruby-2.0.0-rc1@global/gems/activesupport-3.2.13/lib/active_support/dependencies.rb:245:in `load'
      from /Users/tn/.rvm/gems/ruby-2.0.0-rc1@global/gems/activesupport-3.2.13/lib/active_support/dependencies.rb:245:in `block in load'
      from /Users/tn/.rvm/gems/ruby-2.0.0-rc1@global/gems/activesupport-3.2.13/lib/active_support/dependencies.rb:236:in `load_dependency'
      from /Users/tn/.rvm/gems/ruby-2.0.0-rc1@global/gems/activesupport-3.2.13/lib/active_support/dependencies.rb:245:in `load'
      from /Users/tn/.rvm/gems/ruby-2.0.0-rc1@global/gems/railties-3.2.13/lib/rails/application/routes_reloader.rb:40:in `block in load_paths'
      from /Users/tn/.rvm/gems/ruby-2.0.0-rc1@global/gems/railties-3.2.13/lib/rails/application/routes_reloader.rb:40:in `each'
      from /Users/tn/.rvm/gems/ruby-2.0.0-rc1@global/gems/railties-3.2.13/lib/rails/application/routes_reloader.rb:40:in `load_paths'
      from /Users/tn/.rvm/gems/ruby-2.0.0-rc1@global/gems/railties-3.2.13/lib/rails/application/routes_reloader.rb:16:in `reload!'
      from /Users/tn/.rvm/gems/ruby-2.0.0-rc1@global/gems/railties-3.2.13/lib/rails/application/routes_reloader.rb:26:in `block in updater'
      from /Users/tn/.rvm/gems/ruby-2.0.0-rc1@global/gems/activesupport-3.2.13/lib/active_support/file_update_checker.rb:78:in `call'
      from /Users/tn/.rvm/gems/ruby-2.0.0-rc1@global/gems/activesupport-3.2.13/lib/active_support/file_update_checker.rb:78:in `execute'
      from /Users/tn/.rvm/gems/ruby-2.0.0-rc1@global/gems/railties-3.2.13/lib/rails/application/routes_reloader.rb:27:in `updater'
      from /Users/tn/.rvm/gems/ruby-2.0.0-rc1@global/gems/railties-3.2.13/lib/rails/application/routes_reloader.rb:7:in `execute_if_updated'
      from /Users/tn/.rvm/gems/ruby-2.0.0-rc1@global/gems/railties-3.2.13/lib/rails/application/finisher.rb:66:in `block in &lt;module:Finisher&gt;'
      from /Users/tn/.rvm/gems/ruby-2.0.0-rc1@global/gems/railties-3.2.13/lib/rails/initializable.rb:30:in `instance_exec'
      from /Users/tn/.rvm/gems/ruby-2.0.0-rc1@global/gems/railties-3.2.13/lib/rails/initializable.rb:30:in `run'
      from /Users/tn/.rvm/gems/ruby-2.0.0-rc1@global/gems/railties-3.2.13/lib/rails/initializable.rb:55:in `block in run_initializers'
      from /Users/tn/.rvm/gems/ruby-2.0.0-rc1@global/gems/railties-3.2.13/lib/rails/initializable.rb:54:in `each'
      from /Users/tn/.rvm/gems/ruby-2.0.0-rc1@global/gems/railties-3.2.13/lib/rails/initializable.rb:54:in `run_initializers'
      from /Users/tn/.rvm/gems/ruby-2.0.0-rc1@global/gems/railties-3.2.13/lib/rails/application.rb:136:in `initialize!'
      from /Users/tn/.rvm/gems/ruby-2.0.0-rc1@global/gems/railties-3.2.13/lib/rails/railtie/configurable.rb:30:in `method_missing'
      from /Users/tn/rails_projects/rails-prelaunch-signup/config/environment.rb:5:in `&lt;top (required)&gt;'
      from /Users/tn/.rvm/gems/ruby-2.0.0-rc1@global/gems/activesupport-3.2.13/lib/active_support/dependencies.rb:251:in `require'
      from /Users/tn/.rvm/gems/ruby-2.0.0-rc1@global/gems/activesupport-3.2.13/lib/active_support/dependencies.rb:251:in `block in require'
      from /Users/tn/.rvm/gems/ruby-2.0.0-rc1@global/gems/activesupport-3.2.13/lib/active_support/dependencies.rb:236:in `load_dependency'
      from /Users/tn/.rvm/gems/ruby-2.0.0-rc1@global/gems/activesupport-3.2.13/lib/active_support/dependencies.rb:251:in `require'
      from /Users/tn/.rvm/gems/ruby-2.0.0-rc1@global/gems/railties-3.2.13/lib/rails/application.rb:103:in `require_environment!'
      from /Users/tn/.rvm/gems/ruby-2.0.0-rc1@global/gems/railties-3.2.13/lib/rails/commands.rb:25:in `&lt;top (required)&gt;'
      from script/rails:6:in `require'
      from script/rails:6:in `&lt;main&gt;'
  </code></pre>
  
  <p>I thought it might be an issue with my routes.rb file but couldn't find an issue with it.</p>
  
  <pre><code>RailsPrelaunchSignup::Application.routes.draw do
  
    root to: "root_path"
  
  end
  </code></pre>
  
  <p><strong>User.rb</strong></p>
  
  <pre><code>class User &lt; ActiveRecord::Base
    rolify
    # Include default devise modules. Others available are:
    # :token_authenticatable, :encryptable, :confirmable, :lockable, :timeoutable and :omniauthable
    devise :database_authenticatable, :registerable, :confirmable,
           :recoverable, :rememberable, :trackable, :validatable
  
    # Setup accessible (or protected) attributes for your model
    attr_accessible :name, :email, :password, :password_confirmation, :remember_me
  
  end
  </code></pre>
  
  <p>Any help would be much appreciated!</p>