Add postgres health check

docker-compose.yml

@@ -9,6 +9,11 @@ services:
     volumes:
       - ./data/postgres:/var/lib/postgresql/data/
     restart: always
+    healthcheck:
+      test: pg_isready -U drone -d dronedb
+      interval: 10s
+      timeout: 5s
+      retries: 5
 
   server:
     image: drone/drone:latest