Custom AppBuilder for Ruby on Rails

app_builder.rb

class AppBuilder < Rails::AppBuilder
  def initialize(generator)
    super(generator)

    at_exit do
      postprocess
    end
  end

  def readme
    create_file 'README.md', 'TODO'
  end
  
  def test
    gem_group :test, :development do
      gem 'debugger'
      gem 'rspec-rails'
      gem 'capybara'
      gem 'poltergeist'
      gem 'database_cleaner'
      gem 'shoulda'
      gem 'factory_girl_rails'
      gem 'timecop'
    end
  end
  
  def leftovers
    # set up additional application folders
    keep_file 'app/services'
    keep_file 'app/presenters'
    keep_file 'app/forms'
    
    # haml
    
    # simple_form
    
    # devise
  
    # git initialization
    git :init
    append_file ".gitignore", "config/database.yml"
    run "cp config/database.yml config/database.yml.example"
    git add: ".", commit: "-m 'initial commit'"
  end
  
  def postprocess
    generate 'rspec:install'
  end
end

app_template.rb

# change README to markdown
remove_file 'README.rdoc'
create_file 'README.md', 'TODO'

# set up additional application folders
keep_file 'app/services'
keep_file 'app/presenters'
keep_file 'app/forms'

# Set up gems
gem 'jquery-ui-rails'
gem 'haml'
gem 'will_paginate'
gem 'has_scope'
gem 'carrierwave'
gem 'cocoon'
gem 'cancan'
gem 'american_date'

# test and development gems
gem_group :test, :development do
  gem 'debugger'
  gem 'rspec-rails'
  gem 'capybara'
  gem 'poltergeist'
  gem 'database_cleaner'
  gem 'shoulda'
  gem 'factory_girl_rails'
  gem 'timecop'
end
    
# simple_form configuration
simple_form_bootstrap = false
if install_simple_form  = yes?('Install Simple Form?')
  gem 'simple_form'
  simple_form_bootstrap = yes?('Use bootstrap configuration for simple form?')
end

# devise confirguration
devise_model_name = 'User'
if install_devise = yes?('Install Devise?')
  gem 'devise'
  if no?('Create default devise User model?')
    devise_model_name = ask('Devise model name?')
  end
end

# run the bundle command
run 'bundle install'

# install rspec
generate 'rspec:install'
keep_file 'spec/acceptance'

# install simple form
if install_simple_form
  simple_form_command = 'simple_form:install'
  simple_form_command += ' --bootstrap' if simple_form_bootstrap
  generate simple_form_command
end

# install devise
if install_devise
  generate 'devise:install'
  generate 'devise', devise_model_name
end

# create the ruby version and gemset files
run 'rvm list'
rvm_ruby_version = ask('Ruby Version?')

run 'rvm gemset list'
rvm_ruby_gemset = ask('Ruby Gemset?')

create_file '.ruby-version', rvm_ruby_version
create_file '.ruby-gemset', rvm_ruby_gemset

# git initialization
git :init
append_file '.gitignore', 'config/database.yml'
append_file '.gitignore', 'public/uploads'
run 'cp config/database.yml config/database.yml.example'
git add: '.', commit: '-m "initial commit"'

Hi @spullen !
Do you know what is the option to use app_builder.rb ? -b in 5.2 seems to have gone.
Thanks.

@dinatih looks like they removed the ability to override the app builder rails 4 onward. Using templates should still work https://guides.rubyonrails.org/rails_application_templates.html

@spullen thank you, didn't see this.