creating and setting up postgres database on mac code example

Example 1: postgresql create database mac

sudo psql -U postgres
psql: FATAL:  role "postgres" does not exist

Example 2: postgresql create database mac

postgres=# CREATE DATABASE DB_NAME;
CREATE DATABASE
postgres=# CREATE USER USER_NAME WITH password 's3cr3t';
CREATE ROLE
postgres=# GRANT ALL ON DATABASE DB_NAME TO USER_NAME;
GRANT
postgres=# \c DB_NAME
You are now connected to database "DB_NAME" as user "postgres".
DB_NAME=# REVOKE ALL ON SCHEMA public FROM public;
REVOKE
DB_NAME=# GRANT ALL ON SCHEMA public TO DB_NAME;
GRANT
DB_NAME=# \q