uninitialized constant using associative forms on rails

This has taken my whole day... I am getting the following error:

uninitialized constant User::Rssfeed

Extracted source (around line #7):

4:  <p>You have no feeds chosen</p>
5:  <p>Select Feeds</p>
6:  <%= @user.id %>
7:  <%= form_for ([@user, @user.rssfeeds.build]) do |f| %>
8:      
9:          <%= f.label :URL %>
10:             <%= f.text_field :url %>

These are my files: routes.rb

PracticeApp::Application.routes.draw do
  devise_for :users do
    resources :rssfeeds
  end
...

user.rb

class User < ActiveRecord::Base
  # Include default devise modules. Others available are:
  # :confirmable, :lockable, :timeoutable and :omniauthable
  has_many :rssfeeds

  devise :database_authenticatable, :registerable,
         :recoverable, :rememberable, :trackable, :validatable

  # Setup accessible (or protected) attributes for your model
  attr_accessible :email, :password, :password_confirmation, :remember_me
  # attr_accessible :title, :body

end

rss_feed.rb

class RssFeed < ActiveRecord::Base
  belongs_to :user
  attr_accessible :title, :url, :user_id
end

I am posting my full Trace after the below comment I hope this is only the stack trace:

activerecord (3.2.22) lib/active_record/inheritance.rb:111:in `compute_type'
activerecord (3.2.22) lib/active_record/reflection.rb:172:in `klass'
activerecord (3.2.22) lib/active_record/reflection.rb:183:in `build_association'
activerecord (3.2.22) lib/active_record/associations/association.rb:239:in `build_record'
activerecord (3.2.22) lib/active_record/associations/collection_association.rb:112:in `build'
activerecord (3.2.22) lib/active_record/associations/collection_proxy.rb:46:in `build'
app/views/welcome/index.html.erb:7:in `_app_views_welcome_index_html_erb___1736128239453068416_26436840'
actionpack (3.2.22) lib/action_view/template.rb:145:in `block in render'
activesupport (3.2.22) lib/active_support/notifications.rb:125:in `instrument'
actionpack (3.2.22) lib/action_view/template.rb:143:in `render'
actionpack (3.2.22) lib/action_view/renderer/template_renderer.rb:47:in `block (2 levels) in render_template'
actionpack (3.2.22) lib/action_view/renderer/abstract_renderer.rb:38:in `block in instrument'
activesupport (3.2.22) lib/active_support/notifications.rb:123:in `block in instrument'
activesupport (3.2.22) lib/active_support/notifications/instrumenter.rb:20:in `instrument'
activesupport (3.2.22) lib/active_support/notifications.rb:123:in `instrument'
actionpack (3.2.22) lib/action_view/renderer/abstract_renderer.rb:38:in `instrument'
actionpack (3.2.22) lib/action_view/renderer/template_renderer.rb:46:in `block in render_template'
actionpack (3.2.22) lib/action_view/renderer/template_renderer.rb:54:in `render_with_layout'
actionpack (3.2.22) lib/action_view/renderer/template_renderer.rb:45:in `render_template'
actionpack (3.2.22) lib/action_view/renderer/template_renderer.rb:18:in `render'
actionpack (3.2.22) lib/action_view/renderer/renderer.rb:36:in `render_template'
actionpack (3.2.22) lib/action_view/renderer/renderer.rb:17:in `render'
actionpack (3.2.22) lib/abstract_controller/rendering.rb:110:in `_render_template'
actionpack (3.2.22) lib/action_controller/metal/streaming.rb:225:in `_render_template'
actionpack (3.2.22) lib/abstract_controller/rendering.rb:103:in `render_to_body'
actionpack (3.2.22) lib/action_controller/metal/renderers.rb:28:in `render_to_body'
actionpack (3.2.22) lib/action_controller/metal/compatibility.rb:50:in `render_to_body'
actionpack (3.2.22) lib/abstract_controller/rendering.rb:88:in `render'
actionpack (3.2.22) lib/action_controller/metal/rendering.rb:16:in `render'
actionpack (3.2.22) lib/action_controller/metal/instrumentation.rb:40:in `block (2 levels) in render'
activesupport (3.2.22) lib/active_support/core_ext/benchmark.rb:5:in `block in ms'
/home/tech/.rvm/rubies/ruby-2.1.5/lib/ruby/2.1.0/benchmark.rb:294:in `realtime'
activesupport (3.2.22) lib/active_support/core_ext/benchmark.rb:5:in `ms'
actionpack (3.2.22) lib/action_controller/metal/instrumentation.rb:40:in `block in render'
actionpack (3.2.22) lib/action_controller/metal/instrumentation.rb:83:in `cleanup_view_runtime'
activerecord (3.2.22) lib/active_record/railties/controller_runtime.rb:24:in `cleanup_view_runtime'
actionpack (3.2.22) lib/action_controller/metal/instrumentation.rb:39:in `render'
actionpack (3.2.22) lib/action_controller/metal/implicit_render.rb:10:in `default_render'
actionpack (3.2.22) lib/action_controller/metal/implicit_render.rb:5:in `send_action'
actionpack (3.2.22) lib/abstract_controller/base.rb:167:in `process_action'
actionpack (3.2.22) lib/action_controller/metal/rendering.rb:10:in `process_action'
actionpack (3.2.22) lib/abstract_controller/callbacks.rb:18:in `block in process_action'
activesupport (3.2.22) lib/active_support/callbacks.rb:425:in `_run__1047168603443753015__process_action__1686181725135518163__callbacks'
activesupport (3.2.22) lib/active_support/callbacks.rb:405:in `__run_callback'
activesupport (3.2.22) lib/active_support/callbacks.rb:385:in `_run_process_action_callbacks'
activesupport (3.2.22) lib/active_support/callbacks.rb:81:in `run_callbacks'
actionpack (3.2.22) lib/abstract_controller/callbacks.rb:17:in `process_action'
actionpack (3.2.22) lib/action_controller/metal/rescue.rb:29:in `process_action'
actionpack (3.2.22) lib/action_controller/metal/instrumentation.rb:30:in `block in process_action'
activesupport (3.2.22) lib/active_support/notifications.rb:123:in `block in instrument'
activesupport (3.2.22) lib/active_support/notifications/instrumenter.rb:20:in `instrument'
activesupport (3.2.22) lib/active_support/notifications.rb:123:in `instrument'
actionpack (3.2.22) lib/action_controller/metal/instrumentation.rb:29:in `process_action'
actionpack (3.2.22) lib/action_controller/metal/params_wrapper.rb:207:in `process_action'
activerecord (3.2.22) lib/active_record/railties/controller_runtime.rb:18:in `process_action'
actionpack (3.2.22) lib/abstract_controller/base.rb:121:in `process'
actionpack (3.2.22) lib/abstract_controller/rendering.rb:45:in `process'
actionpack (3.2.22) lib/action_controller/metal.rb:203:in `dispatch'
actionpack (3.2.22) lib/action_controller/metal/rack_delegation.rb:14:in `dispatch'
actionpack (3.2.22) lib/action_controller/metal.rb:246:in `block in action'
actionpack (3.2.22) lib/action_dispatch/routing/route_set.rb:73:in `call'
actionpack (3.2.22) lib/action_dispatch/routing/route_set.rb:73:in `dispatch'
actionpack (3.2.22) lib/action_dispatch/routing/route_set.rb:36:in `call'
journey (1.0.4) lib/journey/router.rb:68:in `block in call'
journey (1.0.4) lib/journey/router.rb:56:in `each'
journey (1.0.4) lib/journey/router.rb:56:in `call'
actionpack (3.2.22) lib/action_dispatch/routing/route_set.rb:608:in `call'
warden (1.2.4) lib/warden/manager.rb:35:in `block in call'
warden (1.2.4) lib/warden/manager.rb:34:in `catch'
warden (1.2.4) lib/warden/manager.rb:34:in `call'
actionpack (3.2.22) lib/action_dispatch/middleware/best_standards_support.rb:17:in `call'
rack (1.4.7) lib/rack/etag.rb:23:in `call'
rack (1.4.7) lib/rack/conditionalget.rb:25:in `call'
actionpack (3.2.22) lib/action_dispatch/middleware/head.rb:14:in `call'
actionpack (3.2.22) lib/action_dispatch/middleware/params_parser.rb:21:in `call'
actionpack (3.2.22) lib/action_dispatch/middleware/flash.rb:242:in `call'
rack (1.4.7) lib/rack/session/abstract/id.rb:210:in `context'
rack (1.4.7) lib/rack/session/abstract/id.rb:205:in `call'
actionpack (3.2.22) lib/action_dispatch/middleware/cookies.rb:341:in `call'
activerecord (3.2.22) lib/active_record/query_cache.rb:64:in `call'
activerecord (3.2.22) lib/active_record/connection_adapters/abstract/connection_pool.rb:479:in `call'
actionpack (3.2.22) lib/action_dispatch/middleware/callbacks.rb:28:in `block in call'
activesupport (3.2.22) lib/active_support/callbacks.rb:405:in `_run__4304564743745214979__call__3915293872623649341__callbacks'
activesupport (3.2.22) lib/active_support/callbacks.rb:405:in `__run_callback'
activesupport (3.2.22) lib/active_support/callbacks.rb:385:in `_run_call_callbacks'
activesupport (3.2.22) lib/active_support/callbacks.rb:81:in `run_callbacks'
actionpack (3.2.22) lib/action_dispatch/middleware/callbacks.rb:27:in `call'
actionpack (3.2.22) lib/action_dispatch/middleware/reloader.rb:65:in `call'
actionpack (3.2.22) lib/action_dispatch/middleware/remote_ip.rb:31:in `call'
actionpack (3.2.22) lib/action_dispatch/middleware/debug_exceptions.rb:16:in `call'
actionpack (3.2.22) lib/action_dispatch/middleware/show_exceptions.rb:56:in `call'
railties (3.2.22) lib/rails/rack/logger.rb:32:in `call_app'
railties (3.2.22) lib/rails/rack/logger.rb:16:in `block in call'
activesupport (3.2.22) lib/active_support/tagged_logging.rb:22:in `tagged'
railties (3.2.22) lib/rails/rack/logger.rb:16:in `call'
actionpack (3.2.22) lib/action_dispatch/middleware/request_id.rb:22:in `call'
rack (1.4.7) lib/rack/methodoverride.rb:21:in `call'
rack (1.4.7) lib/rack/runtime.rb:17:in `call'
activesupport (3.2.22) lib/active_support/cache/strategy/local_cache.rb:72:in `call'
rack (1.4.7) lib/rack/lock.rb:15:in `call'
actionpack (3.2.22) lib/action_dispatch/middleware/static.rb:83:in `call'
railties (3.2.22) lib/rails/engine.rb:484:in `call'
railties (3.2.22) lib/rails/application.rb:231:in `call'
rack (1.4.7) lib/rack/content_length.rb:14:in `call'
railties (3.2.22) lib/rails/rack/log_tailer.rb:17:in `call'
rack (1.4.7) lib/rack/handler/webrick.rb:59:in `service'
/home/tech/.rvm/rubies/ruby-2.1.5/lib/ruby/2.1.0/webrick/httpserver.rb:138:in `service'
/home/tech/.rvm/rubies/ruby-2.1.5/lib/ruby/2.1.0/webrick/httpserver.rb:94:in `run'
/home/tech/.rvm/rubies/ruby-2.1.5/lib/ruby/2.1.0/webrick/server.rb:295:in `block in start_thread'