Rails not using Postgres user account

I'm using Rails 3.0 and PostgreSQL 8.4 on Ubuntu 10.10 and Ruby 1.9.2p136 with the pg gem. When I run rake db:migrate, I get the error FATAL: password authentication failed for user "my_os_user_account", when I actually expected it to log in to the database as my_db_username 开发者_如何学编程specified in database.yml.

I have md5 authentication configured in pg_hba.conf for both Unix socket and IP connections and I can log in using psql on the command line. I have also tried setting the authentication to trust. psql then allows me to log in without entering a password, but Rails then gives FATAL: role "my_os_user_account" does not exist.

Here's database.yml:

development:
  adapter: postgresql
  database: my_project_dev
  user: my_db_username
  password: my_password
  pool: 5
  timeout: 5000

with additional near-identical entries for test and production.

The correct key for username is, in fact, username and not user. Easy mistake, easy fix.

I had a similar problem. However, my issue was brackets around the actual username and passowrd in database.yml like this "[admin]... [passowrd]", this works for ruby 1.8.7, but not newer versions. Spent an entire aggravating day on this. I realized that might be it after reading this article. (shrug) Hope this helps someone else.