create_postgres_sql_user

f you installed postresql on your server then just host: localhost to database.yml, I usually throw it in around where it says pool: 5. Otherwise if it's not localhost definitely tell that app where to find its database.

development:
  adapter: postgresql
  encoding: unicode
  database: kickrstack_development
  host: localhost
  pool: 5
  username: kickrstack
  password: secret

Make sure your user credentials are set correctly by creating a database and assigning ownership to your app's user to establish the connection. To create a new user in postgresql 9 run:

sudo -u postgres psql

set the postgresql user password if you haven't, it's just backslash password.

postgres=# \password

Create a new user and password and the user's new database:

postgres=# create user guy_on_stackoverflow with password 'keepitonthedl';
postgres=# create database dcaclab_development owner guy_on_stackoverflow; 

Now update your database.yml file after you've confirmed creating the database, user, password and set these privileges. Don't forget host: localhost.