安装

#gemfile
gem 'faker'

使用

#seeds.rb

require 'benchmark'
puts Benchmark.measure { 
  500.times do 
    User.create(
      first_name: Faker::Name.first_name,
      last_name: Faker::Name.last_name,
      email: Faker::Internet.email,
      phone_number: Faker::PhoneNumber.phone_number
    )
  end
}

https://stackoverflow.com/questions/31364265/proper-way-to-seed-has-many-through-relationships-in-rails