Add backend CI workflow for Kotlin/Java projects using Gradle

back001/.forgejo/workflows/backend-ci.yml

@@ -0,0 +1,38 @@
+name: backend-ci
+
+on:
+  push:
+    paths:
+      - "**/*.kt"
+      - "**/*.java"
+      - "**/*.gradle"
+      - "**/*.gradle.kts"
+      - "gradlew"
+      - "gradle/**"
+      - ".forgejo/workflows/backend-ci.yml"
+  pull_request:
+
+jobs:
+  test-and-build:
+    runs-on: docker
+    container:
+      image: gradle:8.7-jdk21
+    steps:
+      - uses: actions/checkout@v4
+
+      # (Opcjonalnie) cache Gradle – przyspiesza mocno kolejne buildy
+      - uses: actions/cache@v4
+        with:
+          path: |
+            /home/gradle/.gradle/caches
+            /home/gradle/.gradle/wrapper
+          key: gradle-${{ runner.os }}-${{ hashFiles('**/*.gradle*', '**/gradle-wrapper.properties') }}
+          restore-keys: |
+            gradle-${{ runner.os }}-
+
+      - name: Test
+        run: ./gradlew test --no-daemon
+
+      - name: Build
+        run: ./gradlew build --no-daemon
+