Lint Dockerfile. Closes #158 🐳

Lint Dockerfile with hadolint
https://github.com/hadolint/hadolint

Author: artkirienko

.github/workflows/docker-image.yml

@@ -5,10 +5,12 @@ on: [push]
 jobs:
 
   build:
- 
     runs-on: ubuntu-latest
- 
     steps:
     - uses: actions/checkout@v1
     - name: Build the Docker image
       run: docker build . --file Dockerfile --tag bakery:$(date +%s)
+    - name: Hadolint Action
+      uses: brpaz/hadolint-action@v1.2.1
+      with:
+        dockerfile: Dockerfile

Dockerfile

@@ -3,7 +3,7 @@ COPY ./ /usr/src/app/
 WORKDIR /usr/src/app
 
 # Update bundler to the latest available version
-RUN gem install bundler
+RUN gem install bundler:2.0.2
 
 RUN bundle
 CMD ["ruby", "lib/bakery_runner.rb"]