Answer to creating multiple has_many records

.gitignore

.bundle

.ruby-version

2.2.4

ar.rb

require 'active_support'
require 'active_record'
require 'minitest/autorun'

ActiveRecord::Base.establish_connection :adapter => 'sqlite3', :database => ':memory:'

class Skill < ActiveRecord::Base
  connection.create_table table_name, :force => true do |t|
    t.string :name
  end
end

class Job < ActiveRecord::Base
  has_many :abilities
  has_many :skills, through: :abilities

  connection.create_table table_name, :force => true do |t|
    t.string :name
  end
end

class Ability < ActiveRecord::Base
  belongs_to :job
  belongs_to :skill

  connection.create_table table_name, :force => true do |t|
    t.integer :job_id
    t.string :skill_id
  end
end


describe 'stuff' do
  before do
    Skill.create!(name: 'selling')
    Skill.create!(name: 'buying')
    Skill.create!(name: 'processing')
    Skill.create!(name: 'repairing')
    Skill.create!(name: 'kick-boxing')
  end

  it 'creates multiple abilities' do
    params = {
      'job' => {
        'name' => 'abc',
        'skill_ids' => ['2', '5']
      },
    }.with_indifferent_access

    job = Job.create(params[:job])
    assert_equal ['buying', 'kick-boxing'], job.skills.map(&:name)
  end
end

Gemfile

source 'https://rubygems.org'

gem 'activerecord', '~> 4.2'
gem 'sqlite3'

Gemfile.lock

GEM
  remote: https://rubygems.org/
  specs:
    activemodel (4.2.5)
      activesupport (= 4.2.5)
      builder (~> 3.1)
    activerecord (4.2.5)
      activemodel (= 4.2.5)
      activesupport (= 4.2.5)
      arel (~> 6.0)
    activesupport (4.2.5)
      i18n (~> 0.7)
      json (~> 1.7, >= 1.7.7)
      minitest (~> 5.1)
      thread_safe (~> 0.3, >= 0.3.4)
      tzinfo (~> 1.1)
    arel (6.0.3)
    builder (3.2.2)
    i18n (0.7.0)
    json (1.8.3)
    minitest (5.8.4)
    sqlite3 (1.3.11)
    thread_safe (0.3.5)
    tzinfo (1.2.2)
      thread_safe (~> 0.1)

PLATFORMS
  ruby

DEPENDENCIES
  activerecord (~> 4.2)
  sqlite3

BUNDLED WITH
   1.10.6