Bundler

Bundler is package management tool for Rails.
Even if other env, we only keep Gemfile and bundler installs all softwares we need.

Gem

Bundler

Bundler is gem file management.
It provides gem package install system for Rails Application.

Step

By default, rails new command executes bundle install
When creating new application, some steps are executed.

• Create files we need
• Create Gemfile
• Install packages according to Gemfile
• Create Gemfile.lock

Bundle install by hand

Skip bundle install when creating application

rails new application --skip-bundle

Gemfile was created

bundle install

If finishing success, Gemfile.lock file was created

Group update

If you want to separate library in gem, you can use group
Gemfile

group :development do
   gem 'sqlite3', '1.3.8'
end

After update, you need to following commands

bundle install --without production
budnle update
bundle install

Gemfile.lock was generated

Package List

bundle list