Fix GitHub workflow to use dynamic branch-based Docker tags

- Replace hardcoded 'nightly' tag with docker/metadata-action
- Automatically tags Docker images based on branch name
- Supports branch pushes, PRs, and SHA-based tags
- Adds required checkout step for metadata action

Author: claude

.github/workflows/DiscordBot.yml

@@ -40,21 +40,35 @@ jobs:
   docker:
     runs-on: ubuntu-latest
     steps:
+      - name: Checkout
+        uses: actions/checkout@v2
+
       - name: Set up QEMU
         uses: docker/setup-qemu-action@v1
-        
+
       - name: Set up Docker Buildx
         uses: docker/setup-buildx-action@v1
-        
+
+      - name: Docker meta
+        id: meta
+        uses: docker/metadata-action@v4
+        with:
+          images: plop91/plop_discord
+          tags: |
+            type=ref,event=branch
+            type=ref,event=pr
+            type=sha,prefix={{branch}}-
+
       - name: Login to DockerHub
-        uses: docker/login-action@v1 
+        uses: docker/login-action@v1
         with:
           username: ${{ secrets.DOCKER_USERNAME }}
           password: ${{ secrets.DOCKER_SECRET }}
-          
+
       - name: Build and push
         id: docker_build
         uses: docker/build-push-action@v2
         with:
           push: true
-          tags: plop91/plop_discord:nightly
+          tags: ${{ steps.meta.outputs.tags }}
+          labels: ${{ steps.meta.outputs.labels }}