Use GitHub action to build and publish the images

once merged/clone you have to define the following
GitHub secrets variables: (adjust values if needed)

    DOCKER_REPO
    DOCKER_USERNAME
    DOCKER_GITHUB_TOKEN

.github/workflows/publish-to-docker.yml

@@ -0,0 +1,36 @@
+# https://github.com/marketplace/actions/publish-docker
+
+name: Publish to Docker
+on: [push]
+jobs:
+  build:
+    runs-on: ubuntu-latest
+
+    strategy:
+      fail-fast: false
+      matrix:
+        perl-version:
+          - '5.30'
+          - '5.28'
+          - '5.26'
+          - '5.24'
+          - '5.22'
+          - '5.20'
+          - '5.18'
+          - '5.16'
+          - '5.14'
+          - '5.12'
+          - '5.10'
+          - '5.8'
+
+    steps:
+    - uses: actions/checkout@master
+    - name: Publish to Registry
+      uses: elgohr/Publish-Docker-Github-Action@master
+      with:
+        name: ${{ secrets.DOCKER_REPO }}
+        username: ${{ secrets.DOCKER_USERNAME }}
+        password: ${{ secrets.DOCKER_GITHUB_TOKEN }}
+        dockerfile: Dockerfile
+        buildargs: BASE=${{ matrix.perl-version }}
+        tags: "v${{ matrix.perl-version }}"

.gitignore

@@ -0,0 +1 @@
+.DS_Store

README.md

@@ -10,9 +10,17 @@ pre-installed bits:
 * various testing modules (see `cpanfile` in this repo)
 
 
-To build and push:
-```bash
-./bin/build-and-push.sh
+## Building Docker images
+
+When pushing to GitHub, it's using a GitHub action `.github/workflows/publish-to-docker.yml`
+to automagically build and publish the docker images for you.
+
+You would have to set in your GitHub repository the following secret variables, with some example values.
+
+```
+DOCKER_REPO=oalders/tester-perl
+DOCKER_USERNAME=oalders
+DOCKER_GITHUB_TOKEN=a-token-or-password
 ```
 
 I'm open to adding more testing modules and dependencies if other people find this to be helpful.