Welcome to Ruby on Rails, a powerful web application framework that empowers developers to create robust and dynamic websites with ease. If you're a beginner looking to dive into the world of web development, this guide will help you get started with the fundamentals of Rails. First, ensure you have the right environment set up by installing Ruby, Rails, and a database like SQLite. This process can be easily accomplished by following the official installation documentation provided by the Ruby on Rails community.

Once your development environment is set up, you can start by generating a new Rails application using the command rails new your_app_name. This command creates a directory with a well-organized structure that includes essential files and folders for your project. As you explore the framework, focus on understanding the Model-View-Controller (MVC) architecture, which is the cornerstone of Rails applications. By grasping MVC concepts, you'll be able to create dynamic, data-driven applications while adhering to best coding practices.

As a Ruby developer, leveraging the right gems can significantly enhance productivity and code quality. Here are the Top 5 Gems Every Ruby Developer Should Know:

1. Rails - A powerful web application framework that allows for the rapid development of database-backed applications, making it an essential gem for creating robust web projects.
2. RSpec - A flexible testing tool that supports behavior-driven development (BDD), enabling developers to write human-readable tests which improve maintainability and collaboration.
3. Devise - A complete authentication solution for Rails-based applications, Devise simplifies the process of managing user accounts, allowing developers to implement user authentication easily.

Continuing with our list of indispensable gems, here are two more that can greatly improve your development workflow:

4. Sidekiq - A background processing library that allows you to handle job queues seamlessly. By offloading time-consuming tasks, Sidekiq can significantly enhance application performance.
5. Pry - An interactive shell for Ruby that offers advanced debugging and code exploration features, Pry is a must-have for any Ruby developer looking to streamline their debugging process.

Familiarity with these gems can elevate your Ruby development skills and lead to more efficient and effective coding practices.

Optimizing your Rails application for performance is crucial for delivering a seamless user experience. Start by profiling your application using tools like Rack Mini Profiler or Ruby Profiler. These tools will help identify bottlenecks in your code. Once you pinpoint areas needing improvement, consider implementing caching strategies such as fragment caching or action caching to reduce load times and improve response rates. Also, ensure your database queries are optimized; use the ActiveRecord query interface wisely and avoid N+1 queries by implementing eager loading with includes.

Another way to enhance the performance of your Rails application is by minimizing asset load times. Use the asset pipeline to compress and concatenate your CSS and JavaScript files. Additionally, consider implementing a content delivery network (CDN) to serve your static assets, which will help distribute the load and decrease latency for users in different geographical locations. Finally, monitor your application's performance regularly with tools like New Relic or Scout APM to ensure that any performance issues are addressed promptly and keep your application running smoothly.