feat: add github action for docker build on release (#132)

* feat: add github action
Add github action for auto build slim torrverser alpine image with ffmpeg for linux/386,linux/amd64,linux/arm/v6,linux/arm/v7,linux/arm64,linux/ppc64le platforms

* build: move creating dirs and files to entrypoint

* fix: remove linux/386 and linux/ppc64le from docker building

* fix: update readme with docker info

.github/workflows/github-actions-docker.yml

@@ -0,0 +1,49 @@
+name: ci
+
+on:
+  release:
+    types: [published]
+
+jobs:
+  docker:
+    runs-on: ubuntu-latest
+    steps:
+      -
+        name: tag number
+        run : echo ${{ github.event.release.tag_name }}
+      -
+        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: Login to GitHub Container Registry
+        uses: docker/login-action@v1
+        with:
+          registry: ghcr.io
+          username: ${{ github.actor }}
+          password: ${{ secrets.GITHUB_TOKEN }}
+      - 
+        name: set lower case owner name
+        run: |
+          echo "REG_REPO=${REPO,,}" >>${GITHUB_ENV}
+        env:
+          REPO: '${{ github.repository }}'
+      - 
+        name: CHECK ENVS
+        run: |
+          echo ${{ env.REG_REPO }}
+      -
+        name: Build and push
+        uses: docker/build-push-action@v2
+        with:
+          context: .
+          platforms: linux/amd64,linux/arm/v6,linux/arm/v7,linux/arm64
+          push: true
+          tags: |
+            ghcr.io/${{ env.REG_REPO }}:${{ github.event.release.tag_name }}
+            ghcr.io/${{ env.REG_REPO }}:latest