Gem rake group example

Gemfile

ruby '2.2.1'

source 'https://rails-assets.org' do
  gem 'rails-assets-bootstrap'
end

source 'https://rubygems.org' do
  gem 'rails', '4.2'

  # Database / Memcache / Solr
  gem 'pg'
   
  # App server
  gem 'unicorn', '~> 4.8.3', require: false

  # Seeding (Rake task only)
  group :rake do
    gem 'seedbank'
  end

  # Assets
  gem 'sass-rails', '~> 5.0.1'
  gem 'uglifier', '~> 2.5.0'
  gem 'yui-compressor', '~> 0.11.0'
  gem 'coffee-rails', '~> 4.0.0'
  gem 'jquery-rails'
  #gem 'jbuilder', '~> 1.2'

  group :development do
    gem 'foreman', require: false
    gem 'spring', '~> 1.3.0', require: false
  end

  group :test, :development do
    gem 'factory_girl_rails', '~> 4.0'
    gem 'launchy'
    gem 'i18n-debug'
    gem 'quiet_assets'
    gem 'oink'
  end

  group :test do
    gem 'simplecov', require: false
  end

  group :production, :staging do
    gem 'heroku-deflater'
    gem 'rails_12factor', '~> 0.0.3'
  end
end

Rakefile

# Add your own tasks in files placed in lib/tasks ending in .rake,
# for example lib/tasks/capistrano.rake, and they will automatically be available to Rake.

require File.expand_path('../config/application', __FILE__)

Bundler.require(:rake)

SomeApp::Application.load_tasks