added forum topic/post

app/models/forum_post.rb

@@ -0,0 +1,12 @@
+class ForumPost < ActiveRecord::Base
+  attr_accessible :body, :topic_id
+  belongs_to :creator, :class_name => "User"
+  belongs_to :topic, :class_name => "ForumTopic"
+  after_save :update_topic_updated_at
+  validates_presence_of :body, :topic_id, :creator_id
+  scope :search_body, lambda {|body| where(["text_index @@ plainto_tsquery(?)", body])}
+  
+  def update_topic_updated_at
+    topic.touch
+  end
+end