Automating the test-branch-name job & docs;

Updating a number of things here. The test-branch-name is the largest
change. It's now using the folders found in the repository to determine
what the tags are that it should avoid. I've also added the
`milmove-atlantis` tag to the ignorance for the `build` job as well.
Lastly, I've added some documentation that discusses some of the CI/CD
updates so folks understand what all the above is doing for them.

.circleci/config.yml

@@ -3,13 +3,20 @@ jobs:
   test-branch-name:
     machine: true
     steps:
+      - checkout
       - run:
           name: Check for reserved branch names
           command: |
-            if [[ $CIRCLE_BRANCH = latest || $CIRCLE_BRANCH = milmove-app || $CIRCLE_BRANCH = milmove-cypress || $CIRCLE_BRANCH = milmove-infra-tf132 || $CIRCLE_BRANCH = milmove-infra-tf112 ]]; then
-              echo "Don't use a branch named 'latest', 'milmove-app', 'milmove-cypress', 'milmove-infra-tf112', 'milmove-infra-tf132'; these are meaningful tags."
-              exit 1
-            fi
+            important_branches=( $(ls -d * | grep milmove) latest )
+            for branch in "${important_branches[@]}"
+            do
+              if test "${CIRCLE_BRANCH}" == ${branch}
+              then
+                echo "Don't use meaningful tags for a branch name!"
+                echo "Don't use a branch named ${branch}."
+                exit 1
+              fi
+            done
 
   build:
     machine: true
@@ -82,6 +89,7 @@ workflows:
               ignore:
                 - latest
                 - milmove-app
+                - milmove-atlantis
                 - milmove-cypress
                 - milmove-infra-tf132
                 - milmove-infra-tf112

README.md

@@ -14,6 +14,27 @@ the public domain. In places where it is eligible for copyright, such as some fo
 this work is licensed under [the MIT License](https://opensource.org/licenses/MIT), the full text of which is included
 in the [LICENSE.txt](./LICENSE.txt) file in this repository.
 
+## CI/CD
+
+This repository uses Workflows to build the containers. The main job is a
+`build` job for historical reasons. The workflows filter on certain branches
+that match the releases of the Docker images. Branches that get created in this
+repository with any of the following names will not build.
+
+* `latest`
+* `milmove-app`
+* `milmove-cypress`
+* `milmove-atlantis`
+* `milmove-cypress`
+* `milmove-infra-tf112`
+* `milmove-infra-tf132`
+
+The main workflow is named `build-containers` and runs `test-branch-name` to
+check if the name of the branch matches any of the name of the containers that
+get built. Take care naming your branches as if the `test-branch-name` job
+fails, it will not allow the `build` command to run which will not allow PRs to
+get merged in.
+
 ## Images
 
 Each image is specifically tailored.
@@ -24,6 +45,7 @@ For the latest stable images:
 * `milmove/circleci-docker:base`
 * `milmove/circleci-docker:milmove-app`
 * `milmove/circleci-docker:milmove-cypress`
+* `milmove/circleci-docker:milmove-infra-tf112`
 * `milmove/circleci-docker:milmove-infra-tf132`
 * `milmove/circleci-docker:milmove-atlantis`