Active Record in script

populate.rb

require 'bundler/inline'

gemfile do
  source 'https://rubygems.org'
  gem 'activerecord'
  gem 'pg'
end

require 'active_record'

class ApplicationRecord < ActiveRecord::Base
  self.abstract_class = true
end

class Post < ApplicationRecord
end

def migrate
  ActiveRecord::Schema.define do
    create_table(:posts) do |t|
      t.string :name
      t.string :column1
      t.string :column2
      t.string :column3
      t.jsonb :data
    end
  end
end

migrate

records = 1_000_000.times.map do |i|
  { name: "foo#{i}", column1: 'value1', column2: 'value2', column3: 'value3', data: ['IT', 'FR'] }
end
Post.insert_all(records)
Post.create!(name: 'foo yeah', column1: 'value1', column2:  'value2', column3: 'value3', data: ['foo', 'FR'])