Remove migrate service from docker-compose; update README

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

docker-compose.yml

@@ -13,26 +13,14 @@ services:
       timeout: 5s
       retries: 5
 
-  migrate:
-    build: ./backend
-    entrypoint: ["/migrate"]
-    environment:
-      DATABASE_URL: postgres://ralph:ralph@postgres:5432/ralph?sslmode=disable
-    depends_on:
-      postgres:
-        condition: service_healthy
-    restart: on-failure
-
   api:
     build: ./backend
-    ports:
-      - "8080:8080"
     environment:
       DATABASE_URL: postgres://ralph:ralph@postgres:5432/ralph?sslmode=disable
       LISTEN_ADDR: :8080
     depends_on:
-      migrate:
-        condition: service_completed_successfully
+      postgres:
+        condition: service_healthy
     restart: unless-stopped
 
   webapp: