connect to psql

Install PostgreSQL

Mac OS X, I used the Graphical Installer, recommended on the download page of PostgreSQL. It includes PostgreSQL, pgAdmin and the StackBuilder utility, for installation of additional packages.
try to run

$ pg_config

If you get a not found error, you will need to first find the path of this command with:

$ sudo find / -name pg_config

This should be something like /Library/PostgreSQL/9.3/bin. You need to add it to the $PATH variable, so open the .bash_profile file and add the line:

export PATH=/Library/PostgreSQL/9.3/bin:$PATH

Restart your terminal and try again to type pg_config.

Create a PostgreSQL Database

On mac, the command

$ which psql

should point to the Postgres app. And this other command should start the Postgres command line utility:

$ psql -h localhost

If this command rises an error like psql: FATAL: password authentication falied for user “username”, and you’re sure you have entered your password correctly, you have to enter psql using the postgres user:

$sudo -u postgres psql

On the other hand, if you get an error like psql: FATAL: database does not exist, it might be because your package manager failed to create the proper database, see this post for more info. To solve this problem, try:

$ createdb
$ psql -h localhost
(or $ sudo -u postgres psql)

Or
Connects as a role with same name as the local user, i.e. "postgres", to the database called "postgres" (1st argument to psql).

$sudo -u postgres psql postgres

Then delete database:

DROP DATABASE dbname_db;

create database

CREATE DATABASE dbname_db;
CREATE USER  username;
ALTER ROLE username SET client_encoding TO 'utf8';
ALTER ROLE username SET default_transaction_isolation TO 'read committed';
ALTER ROLE username SET timezone TO 'UTC’;
GRANT ALL PRIVILEGES ON DATABASE dbname_db TO username;

Now, you should be in the command line of Postgres. You can exit this environment by typing

\q

Similarly, you can type \? for more help, \list to list your databases and \du to list your users.

Next, we will create a new database for our project and a new user to whom you will give access to the database:

$ createdb dbname_db
(or $ sudo -u postgres createdb dbname_db)
$ psql
(or $ sudo -u postgres psql)
CREATE ROLE myusername WITH LOGIN PASSWORD 'mypassword';
GRANT ALL PRIVILEGES ON DATABASE dbname_db TO myusername;
ALTER USER myusername CREATEDB;

Where you should change myusername to the user’s name you want, and mypassword to whatever you want. And don’t forget the ; at the end of each statement!

Install the PostgreSQL Django adapter, psycopg2

we need to install a PostgreSQL database adapter for Python: the psycopg2 package:

$ pip install psycopg2

Finally, add it into your requirements/base.txt file, and install it into your working environments (testing and developing).

reference
http://www.marinamele.com/taskbuster-django-tutorial/install-and-configure-posgresql-for-django