OperationalError: не удалось подключиться к серверу: подключение отклонено - при попытке подключения к новой базе данных postgresql

Question

Я меняю свою базу данных Django для разработки с sqlite на postgresql.

Я изменил свои настройки на соответствующие значения:

DATABASES = {
    'default': {
        'ENGINE': "django.db.backends.postgresql_psycopg2",
        'NAME': "db.postr",
        'USER': "zorgan",
        'PASSWORD': config('DB_PASSWORD'),
        'HOST': "localhost",
        'PORT': '',
    }
}

однако, когда я выполняю python manage.py makemigrations, я получаю эту ошибку:

Traceback (most recent call last):
  File "manage.py", line 22, in <module>
    execute_from_command_line(sys.argv)
  File "/Users/zorgan/Desktop/postr1/lib/python3.5/site-packages/django/core/management/__init__.py", line 364, in execute_from_command_line
    utility.execute()
  File "/Users/zorgan/Desktop/postr1/lib/python3.5/site-packages/django/core/management/__init__.py", line 356, in execute
    self.fetch_command(subcommand).run_from_argv(self.argv)
  File "/Users/zorgan/Desktop/postr1/lib/python3.5/site-packages/django/core/management/base.py", line 283, in run_from_argv
    self.execute(*args, **cmd_options)
  File "/Users/zorgan/Desktop/postr1/lib/python3.5/site-packages/django/core/management/base.py", line 330, in execute
    output = self.handle(*args, **options)
  File "/Users/zorgan/Desktop/postr1/lib/python3.5/site-packages/django/core/management/commands/makemigrations.py", line 110, in handle
    loader.check_consistent_history(connection)
  File "/Users/zorgan/Desktop/postr1/lib/python3.5/site-packages/django/db/migrations/loader.py", line 282, in check_consistent_history
    applied = recorder.applied_migrations()
  File "/Users/zorgan/Desktop/postr1/lib/python3.5/site-packages/django/db/migrations/recorder.py", line 65, in applied_migrations
    self.ensure_schema()
  File "/Users/zorgan/Desktop/postr1/lib/python3.5/site-packages/django/db/migrations/recorder.py", line 52, in ensure_schema
    if self.Migration._meta.db_table in self.connection.introspection.table_names(self.connection.cursor()):
  File "/Users/zorgan/Desktop/postr1/lib/python3.5/site-packages/django/db/backends/base/base.py", line 254, in cursor
    return self._cursor()
  File "/Users/zorgan/Desktop/postr1/lib/python3.5/site-packages/django/db/backends/base/base.py", line 229, in _cursor
    self.ensure_connection()
  File "/Users/zorgan/Desktop/postr1/lib/python3.5/site-packages/django/db/backends/base/base.py", line 213, in ensure_connection
    self.connect()
  File "/Users/zorgan/Desktop/postr1/lib/python3.5/site-packages/django/db/utils.py", line 94, in __exit__
    six.reraise(dj_exc_type, dj_exc_value, traceback)
  File "/Users/zorgan/Desktop/postr1/lib/python3.5/site-packages/django/utils/six.py", line 685, in reraise
    raise value.with_traceback(tb)
  File "/Users/zorgan/Desktop/postr1/lib/python3.5/site-packages/django/db/backends/base/base.py", line 213, in ensure_connection
    self.connect()
  File "/Users/zorgan/Desktop/postr1/lib/python3.5/site-packages/django/db/backends/base/base.py", line 189, in connect
    self.connection = self.get_new_connection(conn_params)
  File "/Users/zorgan/Desktop/postr1/lib/python3.5/site-packages/django/db/backends/postgresql/base.py", line 176, in get_new_connection
    connection = Database.connect(**conn_params)
  File "/Users/zorgan/Desktop/postr1/lib/python3.5/site-packages/psycopg2/__init__.py", line 130, in connect
    conn = _connect(dsn, connection_factory=connection_factory, **kwasync)
django.db.utils.OperationalError: could not connect to server: Connection refused
        Is the server running on host "localhost" (::1) and accepting
        TCP/IP connections on port 5432?
could not connect to server: Connection refused
        Is the server running on host "localhost" (fe80::1) and accepting
        TCP/IP connections on port 5432?
could not connect to server: Connection refused
        Is the server running on host "localhost" (127.0.0.1) and accepting
        TCP/IP connections on port 5432?

Я считаю, что проблема в том, что у меня нет базы данных Postgres, однако когда я выполняю sudo -u postgres psql в моей среде разработки, она возвращает:

sudo: unknown user: postgres
sudo: unable to initialize policy plugin

и это то, что я должен сделать , чтобы создать базу данных postgres .

Есть предложения?