ci: add action for uploading to docker

.gitea/workflows/docker.yml

@@ -0,0 +1,28 @@
+name: Build and Push Docker Image
+
+on:
+  push:
+    branches: [master]
+
+jobs:
+  build:
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v4
+
+      - name: Login to Gitea Registry
+        uses: docker/login-action@v3
+        with:
+          registry: gitea.vrossem.net
+          username: ${{ gitea.actor }}
+          password: ${{ secrets.REGISTRY_TOKEN }}
+
+      - name: Build and push
+        uses: docker/build-push-action@v5
+        with:
+          context: .
+          push: true
+          tags: |
+            gitea.vrossem.net/${{ gitea.repository }}:latest
+            gitea.vrossem.net/${{ gitea.repository }}:${{ gitea.sha }}