Instalando o PostgreSQL no Ubuntu para Ruby on Rails

$ sudo apt-get install postgresql
$ sudo apt-get install libpq-dev

$ sudo su postgres -c psql
postgres=# CREATE ROLE <username> SUPERUSER LOGIN;
postgres=# \q

# Remove gem 'sqlite3'
gem 'pg'

development:
  adapter: postgresql
  encoding: unicode
  database: appname_development
  pool: 5
  timeout: 5000
  username: <username>
  password:

test:
  adapter: postgresql
  encoding: unicode
  database: appname_test
  pool: 5
  timeout: 5000
  username: <username>
  password:

$ bundle install

$ rake db:create:all
$ rake db:migrate