## post model
class Post < DataMapper::Base
  property :title, :string
  property :body, :text
  property :created_at, :datetime
  property :updated_at, :datetime

  belongs_to :blog
  validates_presence_of :blog_id, :title, :body, :title
end


## blog model
class Blog < DataMapper::Base
  # properties here
  property :created_at, :datetime
  property :updated_at, :datetime

  has_many :posts
  validates_presence_of :name
end