This book is an exploration of Ruby on Rails 5. It begins by guiding you on how to setup the Rails development environment on your local computer in various platforms. You are then guided on how to test the various parts of your Rails 5 app. Test-Driven Development is also explored in detail. The MVC (Model-View-Controller) architecture for apps is discussed. You will learn how to implement a Rails 5 app using such architecture for ease of development, maintenance, and organization. Each of the modern web apps is in need of an authentication system. This helps us to regulate how the resources of your app are accessed. This book guides you on how to create an authentication system with Rails. It is also good for us to implement a mechanism for activating accounts via email. This also allows us to know whether a user has provided a valid email address or not. This book guides you on how to implement such a system in Rails 5. You will learn how to deploy a Rails 5 app with Heroku. The following topics are explored in this book: - Install and Setup your Rails Development Environment - Testing and Test-Driven Development - Model-View-Controller (MVC) Pattern - Static Pages - Implementing an Authentication System - Account Activation and Password Reset - Application Deployment