undefined method `discussion_postcomments_path' for #<#<Class:0x7a1c360>:0x7a20c38> - ruby-on-rails

Question

I recently added a new Model (discussion.rb) and Controller (discussions_controller.rb). I am trying to get postcomments to work with discussions.
discussion.rb
class Discussion < ActiveRecord::Base
belongs_to :user
has_many :postcomments, dependent: :destroy
validates :user_id, presence: true
validates :content, presence: true
attr_accessible :content, :user_id
default_scope order: 'discussions.created_at DESC'
end
Here's what I have in routes
resources :discussions, :path => "disc"
resources :users do
member do
get :following, :followers
end
end
resources :sessions, only: [:new, :create, :destroy]
resources :microposts, only: [:create, :destroy]
resources :discussions, only: [:create, :destroy]
resources :relationships, only: [:create, :destroy]
resources :microposts do
resources :postcomments
resources :discussions do
resources :postcomments
end
end
here's the postcomments model
class Postcomment < ActiveRecord::Base
attr_accessible :comment_content
belongs_to :user
belongs_to :micropost
belongs_to :discussion
validates :comment_content, presence: true
validates :user_id, presence: true
default_scope order: 'postcomments.created_at ASC'
end
I'm trying to use this in view except, I get the error posted in the title
<%= form_for([discussion, #comment]) do |f| %>
<%= render 'shared/error_messages', object: f.object %>
<div class="field">
<%= f.text_field :comment_content %>
</div>
<div class="ItemContainer">
<div class="ItemInput">
<button class="btn" type="submit">
Comment
</button>
</div><div class="ItemCommentCount">
<% end %>
It says that the error is caused from this line
<%= form_for([discussion, #comment]) do |f| %>
Anyone know how I can fix this path problem?
class PostcommentsController < ApplicationController
def create
#micropost = Micropost.find(params[:micropost_id])
#comment = Postcomment.new(params[:postcomment])
#comment.micropost = #micropost
#comment.user = current_user
if #comment.save
redirect_to(:back)
else
render partial: 'shared/_postcomment_form', locals: { micropost: #micropost }
end
end
def createdisc
#discussion = Discussion.find(params[:discussion_id])
#comment = Postcomment.new(params[:postcomment])
#comment.discussion = #discussion
#comment.user = current_user
if #comment.save
redirect_to(:back)
else
render partial: 'shared/_postcomment_form', locals: { discussion: #discussion}
end
end
end

Answer 1

Try consolidating your use of resources :discussions in your routes file. I've edited below assuming you didn't intend to nest discussions under microposts.
resources :discussions, only: [:create, :destroy], path: "disc" do
resources :postcomments
end
resources :users do
member do
get :following, :followers
end
end
resources :sessions, only: [:new, :create, :destroy]
resources :microposts, only: [:create, :destroy]
resources :relationships, only: [:create, :destroy]
resources :microposts do
resources :postcomments
end

Answer 2

This line
<%= form_for([discussion, #comment]) do |f| %>
This discussion should be an instance variable as well:
<%= form_for([#discussion, #comment]) do |f| %>
Then you need to define #discussion in the controller