migrate_hstore_to_json.rb

class MigrateHstoreToJson < ActiveRecord::Migration
  def up
    rename_column :posts, :data, :data_hstore
    add_column    :posts, :data, :jsonb, default: {}, null: false, index: { using: 'gin' }
    execute       'UPDATE "posts" SET "data" = json_object(hstore_to_matrix("data_hstore"))::jsonb'
    remove_column :posts, :data_hstore
  end
  
  def down
    rename_column :posts, :data, :data_jsonb
    add_column    :posts, :data, :hstore, default: {}, null: false
    execute       'UPDATE "posts" SET "data" = (SELECT hstore(key, value) FROM jsonb_each_text("data_jsonb"))'
    remove_column :posts, :data_jsonb
  end
end