Example files for various CI pipelines should be added to documentation

[kirillian]

Shiplane should have example CI snippets for the following CI pipelines plus any others that users submit:

• TravisCI
• CircleCI

[andrewmcodes]

What should the ci pipeline do?

[kirillian]

Good clarification point. The CI pipeline should build the containers and upload them to the container registry of choice. The relevant command will look something akin to the following:

bin/rails shiplane:build[<sha>,<stage(production/staging/other)>]

Of note, you will need to make any environment variables that are necessary at buildtime available in some manner. While the Docker ecosystem is moving away from using those at buildtime, if your project still uses them, they will need to somehow be available to CI in order for it to build the image.