rails self join - ruby-on-rails

Question

I want a user to be able to create a challenge (challenges_created) and other users to be able to offer support to achieve them (challenges_supported). I tried to do this with a self joined challenge model with its resources nested beneath the users resource. I currently have models:
class User < ActiveRecord::Base
attr_accessible :name, :supporter_id, :challenger_id
has_many :challenges_created, :class_name => 'Challenge', :foreign_key => :challenger_id
has_many :challenges_supported, :class_name => 'Challenge', :foreign_key => :supporter_id
end
and
class Challenge < ActiveRecord::Base
attr_accessible :challenger, :completion_date, :description, :duration, :status, :supporter, :title
belongs_to :challenger, :class_name => 'User'
has_many :supporters, :class_name => 'User'
end
I think that I would need full CRUD and corresponding views both for when users are creating challenges and when they are supporting them. Because of this, I created 2 controllers named challenges_created_controller and challenges_supported_controller.
My routes.rb file is:
resources :users do
resources :challenges_created
resources :challenges_supported
end
The problem that I am encountering with this setup is that when I try to create a new challenge at
http://localhost:3000/users/3/challenges_created/new
I receive the message
Showing /home/james/Code/Rails/test_models/app/views/challenges_created/_form.html.erb where line #1 raised:
undefined method `user_challenges_path' for #<# <Class:0x007fb154de09d8>:0x007fb1500c0f90>
Extracted source (around line #1):
1: <%= form_for [#user, #challenge] do |f| %>
2: <% if #challenge.errors.any? %>
The result is the same for the edit action too. I have tried many things but if I were to reference #challenge_created in the form_for then it is not matching the Challenge model.
Can anybody please advise on how what I am doing wrong. Thank you in advance. My schema is:
create_table "users", :force => true do |t|
t.string "name"
t.datetime "created_at", :null => false
t.datetime "updated_at", :null => false
t.integer "challenger_id"
t.integer "supporter_id"
end
create_table "challenges", :force => true do |t|
t.string "title"
t.text "description"
t.integer "duration"
t.date "completion_date"
t.string "status"
t.datetime "created_at", :null => false
t.datetime "updated_at", :null => false
t.integer "challenger_id"
t.integer "supporter_id"
end

Answer 1

I think the problem is that you have a challenge_created controller, but you do not have model for it. In you form you specify a user and a challenge so rails tries to find a controller for challenge, not challenge_created. Rails thinks that for a model you have a controller named based on the convention.
I recommend you not to create two different controllers for challenges. Use only one and differenciate on actions. E.g. ou can create a list_created and list_supported action in challenges.