Automatically update dockerhub description

.github/workflows/dockerhub-description.yml

@@ -0,0 +1,22 @@
+
+name: Update Docker Hub Description
+on:
+  push:
+    branches:
+      - master
+    paths:
+      - README.md
+      - .github/workflows/dockerhub-description.yml
+jobs:
+  dockerHubDescription:
+    runs-on: ubuntu-latest
+    steps:
+    - uses: actions/checkout@v2
+
+    - name: Docker Hub Description
+      uses: peter-evans/dockerhub-description@v2
+      with:
+        username: charlocharlie
+        password: ${{ secrets.DOCKERHUB_PASSWORD }}
+        repository: charlocharlie/markov-discord
+        readme-filepath: ./README.md