Rails和PostgreSQL：角色postgres不存在
我已经在Mac OS Lion上安装了PostgreSQL，并且正在使用Rails应用程序。我使用RVM使所有内容与其他Rails应用程序分开。
I have installed PostgreSQL on my Mac OS Lion, and am working on a rails app. I use RVM to keep everything separate from my other Rails apps.
由于某些原因，当我第一次尝试迁移数据库时，rake无法找到postgres用户。我收到错误消息
For some reason when I try to migrate the db for the first time rake cannot find the postgres user. I get the error
FATAL: role "postgres" does not exist
我有pgAdmin，因此我可以清楚地看到数据库中有一个postgres用户-实际上是admin帐户-因此，我不确定还要做什么。
I have pgAdmin so I can clearly see there is a postgres user in the DB - the admin account in fact - so I'm not sure what else to do.
我读过一些关于PostgreSQL有问题的人，因为它安装在哪条路径上，但是我认为如果它不能解决的话，我不会走那么远
I read somewhere about people having issues with PostgreSQL because of which path it was installed in, but then I don't think I would have gotten that far if it couldn't find the db.
当数据库用户不存在时，将弹出此消息。比较此处的手册。
多个本地数据库 不能作为说明。角色在群集范围内有效。再次手册：
This message pops up, when the database user does not exist. Compare the manual here.
Multiple local databases cannot be the explanation. Roles are valid cluster-wide. The manual again:
请注意，角色是在数据库集群级别定义的，因此
在集群中的所有数据库中均有效。
Note that roles are defined at the database cluster level, and so are valid in all databases in the cluster.
您必须以另一个数据库集群结尾。那将是在同一台计算机上运行的另一台服务器，侦听不同的端口。或者更有可能在另一台机器上。
You must be ending up in another database-cluster. That would be another server running on the same machine, listening to a different port. Or, more likely, on a different machine.
消息是否实际上来自远程服务器？
Could it be that the message comes, in fact, from the remote server?