.preload.rb

# frozen_string_literal: true

def db_migrations
  return @db_migrations if defined?(@db_migrations)

  puts "Request to DB from #{self.class} (#{object_id})"
  @db_migrations = [3, 5]
end

check.rb

# frozen_string_literal: true

require_relative '.preload'

## Class for migration (file)
class Migration
  def initialize(version)
    @version = version
  end

  def applied?
    db_migrations.include?(@version)
  end

  def print
    puts "Migration #{@version} #{applied? ? 'is' : 'is not'} applied"
  end
end

migrations = (1..6).map { |version| Migration.new(version) }

migrations.each(&:print)