Let's summarize what we have learned so far. We already know that the Dockerfile is the source code of the Image. It contains ordered instructions on how to build an image. An image is a specific state of a filesystem: a read-only, frozen immutable snapshot of a live container. It's composed of layers representing changes in the filesystem at various points in time; layers are a bit like the commit history of a Git repository. Containers, on the other hand are runtime instances of an image. They can have state (for example, running or stopped). You can make changes to the filesystem on a container and commit them to make them persisted, but only changes in the filesystem can be committed - memory changes will be lost. Commit always creates a new image. We also mentioned the concept of a registry, which holds a collection of named repositories, which themselves are a collection of images tracked by their IDs. A registry is like a Git repository: you can push and pull containers. We...