I'm basing feeds/show.rhtml and feeds_controller.rb on
Chapter 12 - More Model Magic Ruby on Rails For Dummies by Barry Burd John Wiley & Sons © 2007
specifically listings 12-12 and 12-14. Of course, it's now deprecated 
There's a has_many_through between the "feeds" and "tags" tables. The join table is "colors", for lack of a better name. I believe that the name of the join table and that it's a has_many_through are causing the error message.
I have a screen shot at Google Code Archive - Long-term storage for Google Code Project Hosting. , just click on the add_a_tag.png. Up to that point, everything works. However, when I click on the button I get the following error:
NoMethodError in FeedsController#add_some_tags
undefined method `push_with_attributes' for Tag:Class
RAILS_ROOT: ./script/../config/.. Application Trace | Framework Trace | Full Trace
/usr/lib/ruby/gems/1.8/gems/activerecord-1.15.5/lib/active_record/ base.rb:1238:in `method_missing' /usr/lib/ruby/gems/1.8/gems/activerecord-1.15.5/lib/active_record/ associations/has_many_through_association.rb:120:in `send' /usr/lib/ruby/gems/1.8/gems/activerecord-1.15.5/lib/active_record/ associations/has_many_through_association.rb:120:in `method_missing' /usr/lib/ruby/gems/1.8/gems/activerecord-1.15.5/lib/active_record/ base.rb:946:in `with_scope' /usr/lib/ruby/gems/1.8/gems/activerecord-1.15.5/lib/active_record/ associations/has_many_through_association.rb:120:in `method_missing' /home/thufir/Desktop/strawr/app/controllers/feeds_controller.rb:88:in `add_some_tags' /home/thufir/Desktop/strawr/app/controllers/feeds_controller.rb:87:in `each' /home/thufir/Desktop/strawr/app/controllers/feeds_controller.rb:87:in `add_some_tags'
/usr/lib/ruby/gems/1.8/gems/activerecord-1.15.5/lib/active_record/ base.rb:1238:in `method_missing' /usr/lib/ruby/gems/1.8/gems/activerecord-1.15.5/lib/active_record/ associations/has_many_through_association.rb:120:in `send' /usr/lib/ruby/gems/1.8/gems/activerecord-1.15.5/lib/active_record/ associations/has_many_through_association.rb:120:in `method_missing' /usr/lib/ruby/gems/1.8/gems/activerecord-1.15.5/lib/active_record/ base.rb:946:in `with_scope' /usr/lib/ruby/gems/1.8/gems/activerecord-1.15.5/lib/active_record/ associations/has_many_through_association.rb:120:in `method_missing' /usr/lib/ruby/gems/1.8/gems/actionpack-1.13.5/lib/action_controller/ base.rb:1101:in `send' /usr/lib/ruby/gems/1.8/gems/actionpack-1.13.5/lib/action_controller/ base.rb:1101:in `perform_action_without_filters' /usr/lib/ruby/gems/1.8/gems/actionpack-1.13.5/lib/action_controller/ filters.rb:696:in `call_filters' /usr/lib/ruby/gems/1.8/gems/actionpack-1.13.5/lib/action_controller/ filters.rb:688:in `perform_action_without_benchmark' /usr/lib/ruby/gems/1.8/gems/actionpack-1.13.5/lib/action_controller/ benchmarking.rb:66:in `perform_action_without_rescue' /usr/lib/ruby/1.8/benchmark.rb:293:in `measure' /usr/lib/ruby/gems/1.8/gems/actionpack-1.13.5/lib/action_controller/ benchmarking.rb:66:in `perform_action_without_rescue' /usr/lib/ruby/gems/1.8/gems/actionpack-1.13.5/lib/action_controller/ rescue.rb:83:in `perform_action' /usr/lib/ruby/gems/1.8/gems/actionpack-1.13.5/lib/action_controller/ base.rb:435:in `send' /usr/lib/ruby/gems/1.8/gems/actionpack-1.13.5/lib/action_controller/ base.rb:435:in `process_without_filters' /usr/lib/ruby/gems/1.8/gems/actionpack-1.13.5/lib/action_controller/ filters.rb:684:in `process_without_session_management_support' /usr/lib/ruby/gems/1.8/gems/actionpack-1.13.5/lib/action_controller/ session_management.rb:114:in `process' /usr/lib/ruby/gems/1.8/gems/actionpack-1.13.5/lib/action_controller/ base.rb:334:in `process' /usr/lib/ruby/gems/1.8/gems/rails-1.2.5/lib/dispatcher.rb:41:in `dispatch' /usr/lib/ruby/gems/1.8/gems/rails-1.2.5/lib/webrick_server.rb:113:in `handle_dispatch' /usr/lib/ruby/gems/1.8/gems/rails-1.2.5/lib/webrick_server.rb:79:in `service' /usr/lib/ruby/1.8/webrick/httpserver.rb:104:in `service' /usr/lib/ruby/1.8/webrick/httpserver.rb:65:in `run' /usr/lib/ruby/1.8/webrick/server.rb:173:in `start_thread' /usr/lib/ruby/1.8/webrick/server.rb:162:in `start' /usr/lib/ruby/1.8/webrick/server.rb:162:in `start_thread' /usr/lib/ruby/1.8/webrick/server.rb:95:in `start' /usr/lib/ruby/1.8/webrick/server.rb:92:in `each' /usr/lib/ruby/1.8/webrick/server.rb:92:in `start' /usr/lib/ruby/1.8/webrick/server.rb:23:in `start' /usr/lib/ruby/1.8/webrick/server.rb:82:in `start' /usr/lib/ruby/gems/1.8/gems/rails-1.2.5/lib/webrick_server.rb:63:in `dispatch' /usr/lib/ruby/gems/1.8/gems/rails-1.2.5/lib/commands/servers/webrick.rb:59 /usr/lib/ruby/site_ruby/1.8/rubygems/custom_require.rb:27:in `gem_original_require' /usr/lib/ruby/site_ruby/1.8/rubygems/custom_require.rb:27:in `require' /usr/lib/ruby/gems/1.8/gems/activesupport-1.4.4/lib/active_support/ dependencies.rb:495:in `require' /usr/lib/ruby/gems/1.8/gems/activesupport-1.4.4/lib/active_support/ dependencies.rb:342:in `new_constants_in' /usr/lib/ruby/gems/1.8/gems/activesupport-1.4.4/lib/active_support/ dependencies.rb:495:in `require' /usr/lib/ruby/gems/1.8/gems/rails-1.2.5/lib/commands/server.rb:39 /usr/lib/ruby/site_ruby/1.8/rubygems/custom_require.rb:27:in `gem_original_require' /usr/lib/ruby/site_ruby/1.8/rubygems/custom_require.rb:27:in `require' script/server:3
/usr/lib/ruby/gems/1.8/gems/activerecord-1.15.5/lib/active_record/ base.rb:1238:in `method_missing' /usr/lib/ruby/gems/1.8/gems/activerecord-1.15.5/lib/active_record/ associations/has_many_through_association.rb:120:in `send' /usr/lib/ruby/gems/1.8/gems/activerecord-1.15.5/lib/active_record/ associations/has_many_through_association.rb:120:in `method_missing' /usr/lib/ruby/gems/1.8/gems/activerecord-1.15.5/lib/active_record/ base.rb:946:in `with_scope' /usr/lib/ruby/gems/1.8/gems/activerecord-1.15.5/lib/active_record/ associations/has_many_through_association.rb:120:in `method_missing' /home/thufir/Desktop/strawr/app/controllers/feeds_controller.rb:88:in `add_some_tags' /home/thufir/Desktop/strawr/app/controllers/feeds_controller.rb:87:in `each' /home/thufir/Desktop/strawr/app/controllers/feeds_controller.rb:87:in `add_some_tags' /usr/lib/ruby/gems/1.8/gems/actionpack-1.13.5/lib/action_controller/ base.rb:1101:in `send' /usr/lib/ruby/gems/1.8/gems/actionpack-1.13.5/lib/action_controller/ base.rb:1101:in `perform_action_without_filters' /usr/lib/ruby/gems/1.8/gems/actionpack-1.13.5/lib/action_controller/ filters.rb:696:in `call_filters' /usr/lib/ruby/gems/1.8/gems/actionpack-1.13.5/lib/action_controller/ filters.rb:688:in `perform_action_without_benchmark' /usr/lib/ruby/gems/1.8/gems/actionpack-1.13.5/lib/action_controller/ benchmarking.rb:66:in `perform_action_without_rescue' /usr/lib/ruby/1.8/benchmark.rb:293:in `measure' /usr/lib/ruby/gems/1.8/gems/actionpack-1.13.5/lib/action_controller/ benchmarking.rb:66:in `perform_action_without_rescue' /usr/lib/ruby/gems/1.8/gems/actionpack-1.13.5/lib/action_controller/ rescue.rb:83:in `perform_action' /usr/lib/ruby/gems/1.8/gems/actionpack-1.13.5/lib/action_controller/ base.rb:435:in `send' /usr/lib/ruby/gems/1.8/gems/actionpack-1.13.5/lib/action_controller/ base.rb:435:in `process_without_filters' /usr/lib/ruby/gems/1.8/gems/actionpack-1.13.5/lib/action_controller/ filters.rb:684:in `process_without_session_management_support' /usr/lib/ruby/gems/1.8/gems/actionpack-1.13.5/lib/action_controller/ session_management.rb:114:in `process' /usr/lib/ruby/gems/1.8/gems/actionpack-1.13.5/lib/action_controller/ base.rb:334:in `process' /usr/lib/ruby/gems/1.8/gems/rails-1.2.5/lib/dispatcher.rb:41:in `dispatch' /usr/lib/ruby/gems/1.8/gems/rails-1.2.5/lib/webrick_server.rb:113:in `handle_dispatch' /usr/lib/ruby/gems/1.8/gems/rails-1.2.5/lib/webrick_server.rb:79:in `service' /usr/lib/ruby/1.8/webrick/httpserver.rb:104:in `service' /usr/lib/ruby/1.8/webrick/httpserver.rb:65:in `run' /usr/lib/ruby/1.8/webrick/server.rb:173:in `start_thread' /usr/lib/ruby/1.8/webrick/server.rb:162:in `start' /usr/lib/ruby/1.8/webrick/server.rb:162:in `start_thread' /usr/lib/ruby/1.8/webrick/server.rb:95:in `start' /usr/lib/ruby/1.8/webrick/server.rb:92:in `each' /usr/lib/ruby/1.8/webrick/server.rb:92:in `start' /usr/lib/ruby/1.8/webrick/server.rb:23:in `start' /usr/lib/ruby/1.8/webrick/server.rb:82:in `start' /usr/lib/ruby/gems/1.8/gems/rails-1.2.5/lib/webrick_server.rb:63:in `dispatch' /usr/lib/ruby/gems/1.8/gems/rails-1.2.5/lib/commands/servers/webrick.rb:59 /usr/lib/ruby/site_ruby/1.8/rubygems/custom_require.rb:27:in `gem_original_require' /usr/lib/ruby/site_ruby/1.8/rubygems/custom_require.rb:27:in `require' /usr/lib/ruby/gems/1.8/gems/activesupport-1.4.4/lib/active_support/ dependencies.rb:495:in `require' /usr/lib/ruby/gems/1.8/gems/activesupport-1.4.4/lib/active_support/ dependencies.rb:342:in `new_constants_in' /usr/lib/ruby/gems/1.8/gems/activesupport-1.4.4/lib/active_support/ dependencies.rb:495:in `require' /usr/lib/ruby/gems/1.8/gems/rails-1.2.5/lib/commands/server.rb:39 /usr/lib/ruby/site_ruby/1.8/rubygems/custom_require.rb:27:in `gem_original_require' /usr/lib/ruby/site_ruby/1.8/rubygems/custom_require.rb:27:in `require' script/server:3
Request
Parameters: {"tag1"=>{"checked"=>"0"}, "commit"=>"Save changes", "tag2"=> {"checked"=>"0"}, "tag3"=>{"checked"=>"1"}, "id"=>"4"}
Show session dump
