add gitea docker workflow

.gitea/workflows/docker-build.yml

@@ -0,0 +1,31 @@
+name: Build and Push LST Docker Image
+
+on:
+  push:
+    branches:
+      - main
+
+jobs:
+  docker:
+    runs-on: ubuntu-latest
+
+    steps:
+      - name: Checkout (local)
+        run: |
+          git clone https://git.tuffraid.net/cowch/lst_v3.git .
+          git checkout ${{ gitea.sha }}
+
+      - name: Login to registry
+        run: echo "${{ secrets.PASSWORD }}" | docker login git.tuffraid.net -u "cowch" --password-stdin
+
+      - name: Build image
+        run: |
+          docker build \
+            -t git.tuffraid.net/cowch/lst_v3:latest \
+            -t git.tuffraid.net/cowch/lst_v3:${{ gitea.sha }} \
+            .
+
+      - name: Push
+        run: |
+          docker push git.tuffraid.net/cowch/lst_v3:latest
+          docker push git.tuffraid.net/cowch/lst_v3:${{ gitea.sha }}