Hai impostato una password per il tuo postgres
utente?
Nel tuo config/database.yml
dovresti avere i tuoi database impostati correttamente:
development:
adapter: postgresql
encoding: unicode
database: your_app_development # name your development app something
host: localhost
pool: 5
username: your_username
password: your_password # or leave blank if you didn't set a password
test:
adapter: postgresql
encoding: unicode
database: your_app_test
host: localhost
pool: 5
username: your_username
password: your_password