Rails: Best association model for Users ->posts -> comments model in a forum kinda of website ?

Question

I'm creating a forum website, where each registered user can write many posts and
each post can have many comments.
Also each user can comment on any posts created by any-other user.

      has_many              has_many
user ------------> Posts -------------- > Comments  
  |                                          ^
  |                                          |   
  |               has_many                   |
  |-------------------------------------------          
      belongs_to
Post ------------> User
  ^                 ^ 
  |                 |
  |                 |
  belongs_to     belongs_to
  |                 |
  |                 |
Comments-------------  

I'm not able to get the user details of a comment using "post.comment.user" or
commenter_email = comments.user.email
How to achieve this ?
Pasting my models for reference :-

class Comment < ActiveRecord::Base  
belongs_to :post  
belongs_to :user  
end  
class Post < ActiveRecord::Base  
  has_many :comments, :dependent => :destroy  
end  
class User < ActiveRecord::Base  
  devise :database_authenticatable, :registerable,  
     :recoverable, :rememberable, :trackable, :validatable  
  attr_accessible :email, :password, :password_confirmation, :remember_me   
  has_many :posts  
  has_many :comments  
end   

Here my schema:-

create_table "comments", :force => true do |t|  
t.integer  "post_id"  
t.integer  "user_id"  
t.text     "comment_text"  
t.datetime "created_at"  
t.datetime "updated_at"  
end  

create_table "posts", :force => true do |t|  
t.integer  "user_id"  
t.integer  "sell_or_buy"  
t.string   "title"  
t.text     "body"  
t.datetime "created_at"  
t.datetime "updated_at"  
end  

create_table "users", :force => true do |t|  
t.string   "email",  
t.string   "encrypted_password",
t.datetime "created_at"  
t.datetime "updated_at"  
end 

I'm using Rails 3.0.1.
please suggest your thoughts.

Answer 1

Since your post has many comments, so it is post.comments instead of post.comment

Since comments is a list of comments, comments.user is not valid also.

You will need the comment's id so that you could find the specific comment's user:

post.comments.find(params[:id]).user

of course, you could also get all users:

post.comments.all.collect(&:user)