I'm trying to use pgAdmin III to manage my Postgres database.

Here are the commands I've run on my machine:

sudo apt-get install postgresql

Then I installed the pgAdmin III application:

sudo apt-get install pgadmin3

Next I focused on setting my username and password in order to login:

sudo -u postgres psql postgres

Here I set my password
\password postgres

Finally I just created my database:

sudo -u postgres createdb repairsdatabase

When I try to login using pgAdmin III, I get the error:

An error has occurred:

Error connecting to the server: FATAL: Peer authentication failed for user "postgres"