Postgresql Rails issues

I need to convert an app from sqlite to Postgresql in order to use search with thinkingsphinx. I have run the following steps what am I missing?

I added the pg gem to my gemfile, ran brew install postgresql, and have configured my database.yml file as follows:

development:
开发者_Go百科  adapter: postgresql
  database: example_development
  username: 
  password:
  host: localhost
  encoding: UTF8

I have also run the commands that homebrew suggests on installation:

If this is your first install, create a database with:
initdb /usr/local/var/postgres

If this is your first install, automatically load on login with:
mkdir -p ~/Library/LaunchAgents
cp /usr/local/Cellar/postgresql/9.0.4/org.postgresql.postgres.plist ~/Library/LaunchAgents/
launchctl load -w ~/Library/LaunchAgents/org.postgresql.postgres.plist

What do I put for my username and password? Is there a file I need to edit or do I need to create a database from the command line? There must be something simple that I am missing. I haven't run any custom sql queries, and have stuck to active record defaults.

---

You need to specify the username and password of the account on the Postgres database you are using.

If you do not have a local postgres installation running, then there is no database to connect to, so you will have to follow some instructions online that outline installing and setting up a postgres database on your development machine.