Rais route for through association

Rais route for through association

I am fairly new to Rails and I am creating a blog site and I need a post
to have a category(s) and the end result url will be something like this -
foo.com/category(title)/post(title) so after alot of Googling and then
watching this railscast
http://railscasts.com/episodes/47-two-many-to-many. I have the following
models but have no idea what the routes should be.
Should I now be using the index view of category to display all posts?
Model - Categorisations
class Categorisations < ActiveRecord::Base
attr_accessible :category_id, :product_id
end
Model - Category
class Category < ActiveRecord::Base
attr_accessible :title, :image
has_many :categorisations
has_many :posts, :through => :categorisations
end
Model - Post
class Post < ActiveRecord::Base
attr_accessible :body, :is_verified, :publish_date, :title, :url,
:tag_list, :image, :category_id
has_many :categorisations
has_many :categories, :through => :categorisations
end