Pin postgres version, add persistent storage

compose.yml

@@ -54,25 +54,15 @@ services:
     networks:
       - backend
   postgres:
-    image: postgres
+    image: postgres:11
     networks:
       - backend
     environment:
       POSTGRES_USER: user
       POSTGRES_PASSWORD: pass
       POSTGRES_DB: outline
-  s3:
-    image: lphoward/fake-s3
-    networks:
-      - backend
     volumes:
-      - fakes3_data:/fakes3_root
-    #healthcheck:
-    #  test: ["CMD", "curl", "-f", "http://localhost:4569"]
-    #  interval: 30s
-    #  timeout: 10s
-    #  retries: 10
-    #  start_period: 1m
+      - 'postgresql_data:/var/lib/postgresql/data'
 
 networks:
   proxy:
@@ -81,4 +71,4 @@ networks:
     
 volumes:
   outline_data:
-  fakes3_data:
+  postgres_data: