在ubuntu下跑 Postgresql 和 Rails3 基本
Rails 3 Installation

sudo gem install rails

postgres as db installation<>br/

$ sudo apt-get install postgresql

Rails 3 App with postgres as database

$ rails new pg -d postgres

bundle installation
It will install dependency gems & postgres adapter for db connection

bundle install

Here by default 'postgres' database user gets created while installation but i recommend to create new db user with name same as of system user owning project directory permissions.
User owning file permission can be found using

ls -l pg
drwxr-xr-x 7 sandip sandip 4096 2011-02-23 15:38 app
drwxr-xr-x 5 sandip sandip 4096 2011-02-23 18:14 config
-rw-r--r-- 1 sandip sandip 152 2011-02-23 15:38 config.ru
...
Default 'postgres' database user gets created while installation

## Snap of database.yml
development:
adapter: postgresql
encoding: unicode
database: pg_development
username: sandip
pool: 5
Create new database user

pg $ sudo su postgres
pg $ createuser sandip
Shall the new role be a superuser? (y/n) y
pg $ exit
exit

Create a first development database:

pg $ psql template1

Welcome to psql 8.4.6, the PostgreSQL interactive terminal.
...

template1=# \l

List of databases
Name | Owner | Encoding
-----------+----------+----------
postgres | postgres | UTF8
template0 | postgres | UTF8
template1 | postgres | UTF8
(3 rows)

template1=# CREATE DATABASE pg_development;CREATE DATABASEtemplate1=# \l

List of databases
Name | Owner | Encoding
-------------------+----------+----------
postgres | postgres | UTF8
pg_development | sandip | UTF8
template0 | postgres | UTF8
template1 | postgres | UTF8
(4 rows)

template1=# \q

Start rails server

pg $ rails s
Getting hands on postgres terminal
1. Login onto terminal

psql -U DB_USERNAME -d DB_NAME -W DB_PASSWORD
2. List databases

\l
3. Display tables

\dt
4. Exit from terminal

\q