feat: add Docker support with demo mode and database reset functionality

compose.demo.yaml

@@ -0,0 +1,36 @@
+# SPDX-FileCopyrightText: 2026 Paul Schoeneck
+#
+# SPDX-License-Identifier: AGPL-3.0-only AND LicenseRef-KIBU-Additional-Terms
+
+name: kibu-demo
+services:
+  app:
+    image: ${KIBU_IMAGE:-git.voidcube.de/pixo2000/kibu:demo}
+    build:
+      context: .
+    environment:
+      DATABASE_URL: postgresql://kibu_demo:kibu-demo-db-only@demo-db:5432/kibu_demo
+      DEMO_MODE: "true"
+      DEMO_RESET_ON_START: "true"
+      APP_TIMEZONE: Europe/Berlin
+      SESSION_SECURE: ${DEMO_SESSION_SECURE:-false}
+    ports:
+      - "${DEMO_BIND_ADDRESS:-127.0.0.1}:${DEMO_PORT:-3001}:3000"
+    depends_on:
+      demo-db:
+        condition: service_healthy
+    restart: unless-stopped
+  demo-db:
+    image: postgres:17-alpine
+    environment:
+      POSTGRES_DB: kibu_demo
+      POSTGRES_USER: kibu_demo
+      POSTGRES_PASSWORD: kibu-demo-db-only
+    tmpfs:
+      - /var/lib/postgresql/data
+    healthcheck:
+      test: ["CMD-SHELL", "pg_isready -U kibu_demo -d kibu_demo"]
+      interval: 3s
+      timeout: 3s
+      retries: 20
+    restart: unless-stopped