Add Maven CI workflow with MongoDB service

Author: rojae

.github/workflows/maven-ci.yml

@@ -0,0 +1,51 @@
+name: Java CI with Maven
+
+on:
+  push:
+    branches: [ "main" ]
+  pull_request:
+    branches: [ "main" ]
+
+jobs:
+  test:
+    runs-on: ubuntu-latest
+
+    # MongoDB service for integration tests
+    services:
+      mongo:
+        image: mongo:7.0
+        ports:
+          - 27017:27017
+        env:
+          MONGO_INITDB_ROOT_USERNAME: fluxgate
+          MONGO_INITDB_ROOT_PASSWORD: fluxgate123
+          MONGO_INITDB_DATABASE: fluxgate
+        # healthcheck (optional but recommended)
+        options: >-
+          --health-cmd "mongosh --username fluxgate --password fluxgate123 --authenticationDatabase admin --eval 'db.adminCommand(\"ping\")'" 
+          --health-interval=10s
+          --health-timeout=5s
+          --health-retries=5
+
+    # Mongodb
+    env:
+      FLUXGATE_MONGO_URI: "mongodb://fluxgate:fluxgate123@localhost:27017/fluxgate?authSource=admin"
+      FLUXGATE_MONGO_DB: "fluxgate"
+
+    steps:
+      - name: Checkout repository
+        uses: actions/checkout@v4
+
+      - name: Set up JDK
+        uses: actions/setup-java@v4
+        with:
+          java-version: '21'        
+          distribution: 'temurin'
+          cache: maven
+
+      - name: Run tests with Maven
+        run: mvn -B test --file pom.xml
+
+      # Optional: dependency graph for Dependabot etc.
+      - name: Update dependency graph
+        uses: advanced-security/maven-dependency-submission-action@571e99aab1055c2e71a1e2309b9691de18d6b7d6