好的，问题来了：我想上传一个我在本地获得的数据库，并且我在 localhost 中使用，但是，当我使用时：
PGPASSWORD=mypassword pg_dump -Fc --no-acl --no-owner -h localhost -U root app_db > app_db.dump
我总是得到：
pg_dump: [archiver (db)] connection to database "app_db" failed: could not connect to server: Connection refused
Is the server running on host "localhost" and accepting
TCP/IP connections on port 5432?
could not connect to server: Connection refused
Is the server running on host "localhost" and accepting
TCP/IP connections on port 5432?
could not connect to server: Connection refused
Is the server running on host "localhost" and accepting
TCP/IP connections on port 5432?
我认为问题是我写的是 localhost 而不是我的 heroku 应用程序地址，谁能告诉我如何获得正确的地址？