Question

If I used this code to set up a tagging system for my app, how would I then render the posts with the tags I assigned to them. For instance if I assigned a sports tag to a couple posts, how would I then render all posts with the sports tag assigned to it

 rails g model tag name:string
 rails g model tagging article_id:integer tag_id:integer
 rake db:migrate

 class Tagging < ActiveRecord::Base
   belongs_to :article
   belongs_to :tag
 end

 class Tag < ActiveRecord::Base
   has_many :taggings, :dependent => :destroy
   has_many :articles, :through => :taggings
 end

 class Article < ActiveRecord::Base
   has_many :comments, :dependent => :destroy
   has_many :taggings, :dependent => :destroy
   has_many :tags, :through => :taggings
   validates_presence_of :name, :content
   attr_writer :tag_names
   after_save :assign_tags

   def tag_names
     @tag_names || tags.map(&:name).join(' ')
   end

   private

   def assign_tags
     if @tag_names
       self.tags = @tag_names.split(/\s+/).map do |name|
         Tag.find_or_create_by_name(name)
       end
     end
   end
 end

 <p>
   <%= f.label :tag_names %><br />
   <%= f.text_field :tag_names %>
 </p>

Answer 1

Maybe something like this:

# TagsController
def show
  @articles = Tag.find_by_name('sports').articles
end

# tags/show.html.haml
- @articles.each do |article|
  = render :partial => :article