memaker

# app/models/author.rb
class Author < ActiveRecord::Base
  has_many :interests
end

# app/models/interest.rb
class Interest < ActiveRecord::Base
  belongs_to :author
end

memaker

# using has_many :through

rails g model mountain name
rails g model climber name
rails g model adventure climber:references mountain:references

class Climber < ApplicationRecord
	has_many :adventures
	has_many :mountains, :through => :adventures
end

memaker

# using has_and_belongs_to_many

rails g model mountain name
rails g model climber name

class Climber < ApplicationRecord
	has_and_belongs_to_many :mountains
end

class Mountain < ApplicationRecord

memaker

$ rspec spec/models/person_spec.rb
...
Finished in 0.39298 seconds (files took 2.32 seconds to load)

4 examples, 0 failures

memaker

# spec/models/person_spec.rb
require 'rails_helper'

RSpec.describe Person, type: :model do

  it "has a valid factory" do
  	#person = FactoryGirl.build(:person) it is also valid
    expect(FactoryGirl.build(:person)).to be_valid
  end

memaker

# spec/factories/people.rb
require 'faker'

FactoryGirl.define do
  factory :person do
    name { Faker::Name.first_name }
    age { Faker::Number.between(0, 100) }
  end
end

memaker

$ rake db:migrate
== 20161207175605 CreatePeople: migrating =====================================
-- create_table(:people)
   -> 0.0010s
== 20161207175605 CreatePeople: migrated (0.0010s) ============================

$ rake db:test:prepare
$ rspec
...
Finished in 1.58 seconds (files took 1.64 seconds to load)

memaker

# app/models/person.rb

Person < ApplicationRecord
  validates :name, presence: true
  validates :age, presence: true

  def identifier
    [name, age].join " "
  end
end

memaker

$ bundle install
Resolving dependencies...
Using rake 12.0.0
Using concurrent-ruby 1.0.2
Using i18n 0.7.0
...
(more gems here...)
...
Using web-console 3.4.0
Using rails 5.0.0.1

memaker

$ rvm list
rvm rubies

   ruby-1.9.3-p484 [ x86_64 ]
   ruby-2.1.0 [ x86_64 ]
   ruby-2.2.0 [ x86_64 ]
   ruby-2.2.2 [ x86_64 ]
=* ruby-2.3.0 [ x86_64 ]

# => - current