Gem Bundler helps you track and install the gems you need for your Ruby project.
This tutorial shows you how to start a blog page using Ruby on Rails. By covering the design aspects of a Rails web application, it makes it easier to understand the concepts behind Rails and how they fit together. A simple blog/CMS is almost trivial to implement in Rails—scaffolding alone will get you a good way through.
Rails makes it very easy to generate the files that you need to start building a Rails application. Just open the Terminal on a Mac or the Command prompt on Windows.
Using your terminal navigate to your working directory and generate your new rails application.
rails new blog -T
This will generate for you a new Rails application and install a couple of gems for you. The
flag tells Rails to generate the new application without a test suite.
When you generate a new Rails application, by default some gems are
added for you to work with. Gems are like plugins or libraries with some
functionality, installed to satisfy specific needs.