Ray's modifications

vendor/plugins/NewBlog/app/models/comment.rb

@@ -0,0 +1,7 @@
+class Comment
+  include Mongoid::Document
+  include Mongoid::Timestamps
+  field :name, :type => String
+  field :body, :type => String
+  embedded_in :post, :inverse_of => :comments
+end

vendor/plugins/NewBlog/app/models/post.rb

@@ -0,0 +1,8 @@
+class Post
+  include Mongoid::Document
+  include Mongoid::Timestamps
+  field :title, :type => String
+  field :body, :type => String
+  embeds_many :comments
+  validates_presence_of :title, :body
+end