add docker build workflow and version file

.gitea/workflows/build_docker.yml

@@ -0,0 +1,33 @@
+name: Build Docker Image
+on:
+  push:
+    branches:
+      - senpai
+jobs:
+  build:
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout repository
+        uses: actions/checkout@v2
+
+      - name: Set up Docker Buildx
+        uses: docker/setup-buildx-action@v1
+
+      - name: Read current version
+        id: get_version
+        run: echo "current_version=$(cat VERSION)" >> $GITHUB_ENV
+
+      - name: Log in to Gitea Docker Registry
+        run: echo "${{ secrets.DOCKER_PASSWORD }}" | docker login https://gitea.suda.codes -u ${{ secrets.DOCKER_USERNAME }} --password-stdin
+
+      - name: Build and push Docker image
+        uses: docker/build-push-action@v2
+        with:
+          context: .
+          push: true
+          tags: |
+            gitea.suda.codes/sudacode/mpv-youtube-queue-server:${{ env.current_version }}
+            gitea.suda.codes/sudacode/mpv-youtube-queue-server:latest
+
+      - name: Log out from Gitea Docker Registry
+        run: docker logout https://gitea.suda.codes

VERSION

@@ -0,0 +1 @@
+0.0.2