Improve self hosting docs (#732)

docker-compose.example.yml

@@ -2,16 +2,20 @@ services:
 
   app:
     image: ghcr.io/maybe-finance/maybe:latest
+    volumes:
+      - ./storage:/rails/storage
     ports:
       - 127.0.0.1:3000:3000
     restart: unless-stopped
     env_file:
       - .env
     environment:
-      DB_HOST: "postgres"
-      RAILS_ENV: "production"
+      SELF_HOSTING_ENABLED: true
+      DB_HOST: postgres
       RAILS_FORCE_SSL: false
       RAILS_ASSUME_SSL: false
+      POSTGRES_USER: postgres
+      GOOD_JOB_EXECUTION_MODE: async
     depends_on:
       postgres:
         condition: service_healthy
@@ -22,8 +26,8 @@ services:
     volumes:
       - postgres-data:/var/lib/postgresql/data
     environment:
-      POSTGRES_USER: ${POSTGRES_USER:?}
-      POSTGRES_DB: ${POSTGRES_DB:-postgres}
+      POSTGRES_USER: ${POSTGRES_USER:-postgres}
+      POSTGRES_DB: ${POSTGRES_DB:-maybe_production}
       POSTGRES_PASSWORD: ${POSTGRES_PASSWORD:?}
     healthcheck:
       test: [ "CMD-SHELL", "pg_isready -U $$POSTGRES_USER" ]
@@ -32,4 +36,4 @@ services:
       retries: 5
 
 volumes:
-  postgres-data:
+  postgres-data: