adds github actions workflow config

.github/workflows/ci.yaml

@@ -0,0 +1,53 @@
+name: CI Build
+
+on:
+  push:
+    branches:
+      - master
+  pull_request:
+    branches:
+      - master
+
+jobs:
+  tests:
+    runs-on: ubuntu-latest
+    env:
+      TZ: Europe/Oslo
+    steps:
+      - uses: actions/checkout@v4
+      - name: Set up JDK 21
+        uses: actions/setup-java@v4
+        with:
+          java-version: 21
+          distribution: temurin
+          cache: maven
+
+      - name: Run tests
+        run: |
+          sudo timedatectl set-timezone "Europe/Oslo"
+          mvn --batch-mode test
+
+
+  image:
+    # only build and push the image when it's a commit to master in Entur's repository
+    if: github.repository_owner == 'entur' && github.event_name == 'push'
+    runs-on: ubuntu-latest
+    needs: [ tests ]
+    env:
+      CONTAINER_REPO: docker.io/entur/tiamat
+      CONTAINER_REGISTRY_USER: ${{ secrets.DOCKERHUB_LOGIN }}
+      CONTAINER_REGISTRY_PASSWORD: ${{ secrets.DOCKERHUB_PASSWORD }}
+    steps:
+      - uses: actions/checkout@v4
+
+      - name: Set up JDK 21
+        uses: actions/setup-java@v4
+        with:
+          java-version: 21
+          distribution: temurin
+          cache: maven
+
+      - name: Build container image with Jib, push to container repo
+        run: |
+          image_date=`date +%Y-%m-%dT%H-%M`
+          mvn --batch-mode compile com.google.cloud.tools:jib-maven-plugin:build -Djib.to.tags=latest,$image_date