Add central postgres database

stacks/postgres/docker-compose.yaml

@@ -0,0 +1,42 @@
+services:
+  db:
+    image: postgres@sha256:035b9ab53cfa147d7202b61f5f7782b939ae815b7d6bc81c96b7b42ff1fca950
+    container_name: postgres
+    restart: unless-stopped
+    entrypoint: ["/bin/bash", "/init/entrypoint.sh"]
+    environment:
+      POSTGRES_USER: postgres
+      POSTGRES_PASSWORD_FILE: /run/secrets/postgres_password
+    volumes:
+      - postgres_data:/var/lib/postgresql
+      - ./init:/init:ro
+    networks:
+      - homelab_db
+    secrets:
+      - postgres_password
+      - authentik_postgres_password
+      - gitea_postgres_password
+    healthcheck:
+      interval: 30s
+      retries: 5
+      start_period: 20s
+      test:
+        - CMD-SHELL
+        - pg_isready -U postgres
+      timeout: 5s
+
+volumes:
+  postgres_data:
+    driver: local
+
+networks:
+  homelab_db:
+    name: homelab_db
+
+secrets:
+  postgres_password:
+    environment: POSTGRES_PASSWORD
+  authentik_postgres_password:
+    environment: AUTHENTIK_POSTGRES_PASSWORD
+  gitea_postgres_password:
+    environment: GITEA_POSTGRES_PASSWORD