I am using PostgreSQL 9.1.3 (PostgreSQL 9.1.3 on x86_64-pc-linux-gnu, compiled by gcc-4.6.real (Ubuntu/Linaro 4.6.1-9ubuntu3) 4.6.1, 64-bit) and rails either 3.2.2 or 3.2.1 on u
I'd like to propose a slightly different approach which utilizes the file socket instead.
By allowing your Ubuntu user access to the database, everything should work without special connection parameters.
In the Ubuntu command line:
createuser -U postgres your-current-ubuntu-username
see the Manpage of createuser for details.
In your database.yml:
development:
adapter: postgresql
encoding: unicode
database: sample-app_development
pool: 5
username: your-current-ubuntu-username
password: