gistfile1.txt

class CreateGenresShows < ActiveRecord::Migration
  def self.up
    create_table :genres_shows, :id => false do |t|
      t.integer :show_id
      t.integer :genre_id
    end
  end

  def self.down
    drop_table :shows_genres
  end
end

class Show < ActiveRecord::Base
  has_and_belongs_to_many :genres
end

class Genre < ActiveRecord::Base
  has_and_belongs_to_many :shows
end