fix(repository): Move backend code into subdirectory

Signed-off-by: Tilman Vatteroth <git@tilmanvatteroth.de>

.github/workflows/backend-docker.yml

@@ -0,0 +1,96 @@
+# SPDX-FileCopyrightText: 2022 The HedgeDoc developers (see AUTHORS file)
+#
+# SPDX-License-Identifier: AGPL-3.0-only
+
+name: Backend / Docker
+
+on:
+  push:
+    branches: [ develop ]
+  pull_request:
+    branches: [ develop ]
+
+jobs:
+  build-dev:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v3
+
+      - name: Set up Docker Buildx
+        uses: docker/setup-buildx-action@v2
+
+      - name: Login to GHCR
+        uses: docker/login-action@v2
+        with:
+          registry: ghcr.io
+          username: ${{ github.repository_owner }}
+          password: ${{ secrets.GITHUB_TOKEN }}
+
+      - name: Build dev image
+        uses: docker/build-push-action@v3
+        with:
+          push: true
+          file: backend/docker/Dockerfile
+          tags: ghcr.io/${{ github.repository_owner }}/${{ github.event.repository.name }}-ci:${{ github.sha }}
+          target: development
+          cache-from: type=gha
+          cache-to: type=gha,mode=max
+          context: .
+
+  sqlite-test:
+    runs-on: ubuntu-latest
+    needs: [ build-dev ]
+    container:
+      image: ghcr.io/${{ github.repository_owner }}/${{ github.event.repository.name }}-ci:${{ github.sha }}
+    steps:
+      - run: cd /usr/src/app && yarn run test
+
+  sqlite-e2e:
+    runs-on: ubuntu-latest
+    needs: [ build-dev ]
+    container:
+      image: ghcr.io/${{ github.repository_owner }}/${{ github.event.repository.name }}-ci:${{ github.sha }}
+    steps:
+      - run: cd /usr/src/app && yarn run test:e2e
+
+  build-prod:
+    runs-on: ubuntu-latest
+    needs: [ sqlite-test, sqlite-e2e ]
+    steps:
+      - uses: actions/checkout@v3
+
+      - name: Generate Docker metadata
+        id: meta
+        uses: docker/metadata-action@v4
+        with:
+          images: ghcr.io/${{ github.repository_owner }}/${{ github.event.repository.name }}
+          tags: |
+            type=ref,event=branch
+            type=semver,pattern={{version}}
+            type=semver,pattern={{major}}.{{minor}}
+            type=semver,pattern={{major}}
+
+      - name: Set up QEMU
+        uses: docker/setup-qemu-action@v2
+
+      - name: Set up Docker Buildx
+        uses: docker/setup-buildx-action@v2
+
+      - name: Login to GHCR
+        if: github.event_name != 'pull_request'
+        uses: docker/login-action@v2
+        with:
+          registry: ghcr.io
+          username: ${{ github.repository_owner }}
+          password: ${{ secrets.GITHUB_TOKEN }}
+
+      - name: Build and push
+        uses: docker/build-push-action@v3
+        with:
+          push: ${{ github.event_name != 'pull_request' }}
+          file: backend/docker/Dockerfile
+          tags: ${{ steps.meta.outputs.tags }}
+          labels: ${{ steps.meta.outputs.labels }}
+          cache-from: type=gha
+          cache-to: type=gha,mode=max
+          context: .