Merge pull request #629 from dabutvin/docker-image-ci

add docker image ci (fixes #519)

Author: dabutvin

.github/workflows/dockerimage.yml

@@ -0,0 +1,18 @@
+name: Docker Image CI
+
+on:
+  push:
+    branches: [ master ]
+  pull_request:
+    branches: [ master ]
+
+jobs:
+
+  build:
+
+    runs-on: ubuntu-latest
+
+    steps:
+    - uses: actions/checkout@v2
+    - name: Build the Docker image
+      run: docker build -f Dockerfile.CompressImages . -t imgbot