Rails Setup, Ruby, Gems, Bundler, Database Configuration, and Project Creation

Rails Environment Essentials

A Rails application depends on Ruby, the Rails gem, Bundler for dependency management, a database such as SQLite or PostgreSQL, and supporting tooling such as Node-based assets depending on the stack. Students should understand that Rails is not only one gem. It is a coordinated toolchain and ecosystem.

ruby -v
gem -v
bundle -v
rails -v

Creating a New Application

rails new bookstore
cd bookstore
bin/rails server

That one command creates a significant amount of project structure. The value of Rails is that the generated structure is not random. It encodes framework conventions that make future code easier to place and understand.

Bundler and Gemfile

Ruby libraries are packaged as gems. Rails applications declare dependencies in a Gemfile, and Bundler resolves and installs compatible versions. Strong developers understand their dependencies, group them by environment where appropriate, and avoid unnecessary gem sprawl.

gem "devise"
gem "sidekiq"
gem "rspec-rails"

Database Setup and Environment Awareness

The config/database.yml file controls database connections for development, test, and production. Students should learn early that environments matter. Local settings, credentials, secrets, mail configuration, and storage services often differ by environment, and strong Rails engineering keeps those differences explicit and safe.