Continuous Integration

Before pushing your code to production, you should enable CI. This basic setup helps ensure our application code keeps working even when we make changes to our code, by automating the execution of our unit tests.

CircleCI

CircleCI makes it easy to get started, with a free tier and excellent documentation for beginners and pros alike. If you have unique enterprise needs, CircleCI can be brought on-premises, behind corporate firewalls, or as a private deployment in the cloud.

CircleCI has pre-baked build environments for the virtual configuration of free setups, but it can also run builds using Docker containers, making it a solution that scales to the user's skills and needs, as covered in Chapter 9, DevOps Using Docker:

1. Create a CircleCI account at https://circleci.com/.
2. Sign up with GitHub:

   

   Figure 4.5: CircleCI Sign up page

3. Add a new project:

   

   Figure 4.6: CircleCI Projects page

   On the next...