Copy records between databases Posgres -> SQLite3

gistfile1.txt

#
# Database.yml
#
development_ios:
  # <<: *default
  adapter: sqlite3
  pool: 5
  timeout: 5000
  database: db/development_ios.sqlite3

development:
  adapter: postgresql
  encoding: unicode
  database: development
  pool: 5
  username: postgres
  password: postgres
  
#
# db.rake
#

desc "Migrate the database through scripts in db/migrate directory."
namespace :db do
  task :migrate_ios do
    DB_CONF = YAML::load(File.open(File.join(Rails.application.root,'config','database.yml')))

    # db_conf = YAML::load(File.open(File.join(Rails.application.root,'config','database.yml')))
    # puts db_conf["development_ios"]
    # ActiveRecord::Base.establish_connection db_conf["development_ios"]

    Rails.env = "development_ios"
    ActiveRecord::Base.establish_connection DB_CONF["development_ios"]
    Rake::Task["db:drop"].invoke
    Rake::Task["db:create"].invoke
    Rake::Task["db:schema:load"].invoke

    Rails.env = "development"
    ActiveRecord::Base.establish_connection DB_CONF["development"]
    # Classes and shit
    class IOSModel < ActiveRecord::Base
      establish_connection DB_CONF["development_ios"]
    end

    # Copy record by record
    [Person, Event, EventToPerson, PersonToPerson].each do |klass|

      IOSModel.table_name = klass.table_name
      klass.all.find_each do |record|
        puts "#{klass} #{record.id}"
        model = IOSModel.new
        model.attributes = record.attributes
        model.save!
      end
    end
  end
end