The aim of this chapter has been to show more of the depth and usefulness of Rails, while at the same time demonstrate how to extend an existing application with new functionality. The beauty of Rails is that it is easy to tack new functionality on with extra components, whether new actions for existing controllers, new actions for all controllers, or new models and plugins.

This chapter has hopefully given you the confidence to grow your application to meet new requirements and some guidance about how to go about adding new functionality.

In the next chapter, we'll see how to improve the efficiency and performance of a Rails application: making use of caching, using Capistrano for automating repetitive tasks, and setting up the infrastructure for large scale deployment.