Add CI pipeline

Fixes #34

.github/workflows/build.yml

@@ -0,0 +1,34 @@
+name: Gameyfin CI Pipeline
+
+on:
+  push:
+    branches:
+      - master
+  pull_request:
+      types: [opened, synchronize, reopened]
+
+jobs:
+  build:
+    name: Build, Test & Scan
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v3
+      - name: Set up JDK
+        uses: actions/setup-java@v3
+        with:
+          java-version: '18'
+          distribution: 'temurin'
+          cache: 'maven'
+      - name: Maven build
+        run: mvn --batch-mode --update-snapshots package
+      - name: SonarQube scan
+        uses: kitabisa/sonarqube-action@v1.2.0
+        with:
+          host: ${{ secrets.SONARQUBE_HOST }}
+          login: ${{ secrets.SONARQUBE_TOKEN }}
+          projectKey: ${{ secrets.SONARQUBE_PROJECTKEY }}
+      - name: Upload build artifact
+        uses: actions/upload-artifact@v3
+        with:
+          name: backend
+          path: backend/target/gameyfin-*.jar