added artists, comments

app/models/comment.rb

@@ -0,0 +1,41 @@
+class Comment < ActiveRecord::Base
+  class VotingError < Exception ; end
+  
+  validates_format_of :body, :with => /\S/, :message => 'has no content'
+  belongs_to :post
+  belongs_to :creator, :class_name => "User"
+  has_many :votes, :class_name => "CommentVote", :dependent => :destroy
+  after_save :update_last_commented_at
+  after_destroy :update_last_commented_at
+  attr_accessible :body
+  attr_accessor :do_not_bump_post
+  
+  scope :recent, :order => "comments.id desc", :limit => 6
+  scope :search_body, lambda {|query| {:conditions => ["body_index @@ plainto_tsquery(?)", query], :order => "id desc"}}
+
+  def update_last_commented_at
+    return if do_not_bump_post    
+    comment_count = Comment.where(["post_id = ?", post_id]).count    
+    if comment_count <= Danbooru.config.comment_threshold
+      execute_sql("UPDATE posts SET last_commented_at = ? WHERE id = ?", created_at, post_id)
+    end
+  end
+
+  def can_be_voted_by?(user)
+    !votes.exists?(["user_id = ?", user.id])
+  end
+  
+  def vote!(user, is_positive)
+    if can_be_voted_by?(user)
+      if is_positive
+        increment!(:score)
+      else
+        decrement!(:score)
+      end
+      
+      votes.create(:user_id => user.id)
+    else
+      raise VotingError.new("You have already voted for this comment")
+    end
+  end
+end