Docker for Rails Developers

The Finishing Touch

Our Dockerfile is glorious, isn’t it? A masterpiece. This little baby is going to get our Rails app development really going places. So let’s do what all true artists do and sign our work.

Unlike a painter who signs the bottom right of their canvas, Docker aficionados typically assert their authorship of an image by setting a maintainer label as the second instruction. A label is simply a piece of metadata associated with an image.

We set a label using the LABEL instruction, which has the following format:

LABEL <key>=<value>

This gives the image a label named key set to value.

To indicate who is responsible for maintaining the file, we would modify our Dockerfile to specify their email address like so (you can substitute ...