updated readme

app/models/post.rb

@@ -0,0 +1,34 @@
+class Post < ActiveRecord::Base
+  
+  # Associations
+  belongs_to :forum, :counter_cache => true
+  belongs_to :topic, :counter_cache => true, :touch => true 
+  belongs_to :user, :class_name => "User", :counter_cache => true
+  
+  # Accessors
+  attr_accessible :body
+  
+  # Validations
+  validates :body, :presence => true
+  validates :user, :presence => true
+  
+  # Default Scope
+  default_scope :order => 'created_at ASC'
+  
+  # Scope to display only the last n posts. Used for "Recent Posts" display
+  scope :recent, lambda {
+    |c| reorder('created_at desc').limit(c)
+  }
+  
+  # Callbacks
+  before_save :topic_locked?
+  
+  # Methods
+  private
+    def topic_locked?
+      if topic.locked?
+        errors.add(:base, "That topic is locked")
+        false
+      end
+    end
+end