1class Review
 2  attr_accessor :id, :description, :movie
 3end
 4
 5class ReviewMapping < Humble::DatabaseMapping
 6  def run(map)
 7    map.table :reviews
 8    map.type Review
 9    map.primary_key(:id, default: -1)
10    map.column :description
11    map.belongs_to :movie_id, Movie
12  end
13end