This small guide will is to help you to populate your application with sample data that may useful for test during the development.

I’ll be using the following scaffold for the explanations purposes. $ rails g scaffold house family:string members:integer number:integer address:string

So, beginning, as usual, we Need to add in the Gemfile the gem 'populator' and gem 'faker' in group :development and/or ` group :test`, in case you need for the test environment.

After $ bundle install, let open seed.rb file located under db/ then will add a few lines.

# The gem will populate 10 times in the model House and will include sample data provided by faker gem.
House.populate 10 do |m|
    m.family = Faker::Name.last_name
    m.members = 3..6
    m.number = 1..10
    m.address = Faker::Address.street_address
end

After saving the file we will run in the terminal $ rails db:seed

[3] pry(main)> House.all
  House Load (2.0ms)  SELECT "houses".* FROM "houses"
=> [#<House:0x000000035f3bd0 id: 1, family: "Schowalter", members: 3, number: 7, address: "3279 Joey Spring", created_at: Mon, 02 Oct 2017 17:01:24 UTC +00:00, updated_at: Mon, 02 Oct 2017 17:01:24 UTC +00:00>,
 #<House:0x000000035e2330 id: 2, family: "Hagenes", members: 4, number: 4, address: "145 Sipes Islands", created_at: Mon, 02 Oct 2017 17:01:24 UTC +00:00, updated_at: Mon, 02 Oct 2017 17:01:24 UTC +00:00>,
 #<House:0x000000035e1f20 id: 3, family: "Dach", members: 5, number: 6, address: "32723 Alize Groves", created_at: Mon, 02 Oct 2017 17:01:24 UTC +00:00, updated_at: Mon, 02 Oct 2017 17:01:24 UTC +00:00>,
 #<House:0x000000035e1ca0 id: 4, family: "McCullough", members: 6, number: 10, address: "787 Marvin Dale", created_at: Mon, 02 Oct 2017 17:01:24 UTC +00:00, updated_at: Mon, 02 Oct 2017 17:01:24 UTC +00:00>,
 #<House:0x000000035e1958 id: 5, family: "Ebert", members: 4, number: 10, address: "8976 Cartwright Spur", created_at: Mon, 02 Oct 2017 17:01:24 UTC +00:00, updated_at: Mon, 02 Oct 2017 17:01:24 UTC +00:00>,
 ...
[4] pry(main)> 

As you can see the application populate our developemnt database with 10 records and filled with sample data.

Note: in case you got an error after ran the seed and the error is about:

rails aborted!
NoMethodError: undefined method `sanitize' for #<Class:0x007fb8f28082e0>

The error have been reported in the repo in github and there is a workaround for it where you have to replace a line in the file populator/lib/populator/factory.rb

    def rows_sql_arr
        @records.map do |record|
 -        quoted_attributes = record.attribute_values.map { |v| @model_class.sanitize(v) } # replace this line
 +        quoted_attributes = record.attribute_values.map { |v| @model_class.connection.quote(v) } # with this one
          "(#{quoted_attributes.join(', ')})"
        end
      end

As well if you need to implement this project in different places, I recommend to fork the populator gem, make the previous modification, push to your repository in GitHub and use this line in your Gemfile with gem 'populator', :github => 'fulvi0/populator'.