Configure DB Postgres with Ralph 3

Using Ralph
1

Hi, I need configure DB Postgres in Ralph, not in Mysql or sqlite as default. In a server installed Postgress, created a user and database, installed psycopg2, configured settings/base.py and set:

    DATABASES = {
    'default': {
        'ENGINE': os.environ.get('DATABASE_ENGINE', 'transaction_hooks.backends.psycopg2'),  # noqa
        'NAME': os.environ.get('DATABASE_NAME', 'ralph_ng'),
        'USER': os.environ.get('DATABASE_USER', 'ralph_ng'),
        'PASSWORD': os.environ.get('DATABASE_PASSWORD', 'ralph_ng') or None,
        'HOST': os.environ.get('DATABASE_HOST', '127.0.0.1'),
        'PORT': os.environ.get('DATABASE_PORT', 5432),
    }
    }

But not work, not connect the BD, when migrate appear this error:

Traceback (most recent call last):
  File "/opt/ralph/ralph-core/lib/python3.6/site-packages/django/db/backends/postgresql_psycopg2/base.py", line 20, in <module>
    import psycopg2 as Database
ModuleNotFoundError: No module named 'psycopg2'

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "/opt/ralph/ralph-core/bin/ralph", line 10, in <module>
    sys.exit(prod())
  File "/opt/ralph/ralph-core/lib/python3.6/site-packages/ralph/__main__.py", line 28, in prod
    main('ralph.settings.prod')
  File "/opt/ralph/ralph-core/lib/python3.6/site-packages/ralph/__main__.py", line 14, in main
    execute_from_command_line(sys.argv)
  File "/opt/ralph/ralph-core/lib/python3.6/site-packages/django/core/management/__init__.py", line 354, in execute_from_command_line
    utility.execute()
  File "/opt/ralph/ralph-core/lib/python3.6/site-packages/django/core/management/__init__.py", line 328, in execute
    django.setup()
  File "/opt/ralph/ralph-core/lib/python3.6/site-packages/django/__init__.py", line 18, in setup
    apps.populate(settings.INSTALLED_APPS)
  File "/opt/ralph/ralph-core/lib/python3.6/site-packages/django/apps/registry.py", line 85, in populate
    app_config = AppConfig.create(entry)
  File "/opt/ralph/ralph-core/lib/python3.6/site-packages/django/apps/config.py", line 86, in create
    module = import_module(entry)
  File "/opt/ralph/ralph-core/lib/python3.6/importlib/__init__.py", line 126, in import_module
    return _bootstrap._gcd_import(name[level:], package, level)
  File "<frozen importlib._bootstrap>", line 994, in _gcd_import
  File "<frozen importlib._bootstrap>", line 971, in _find_and_load
  File "<frozen importlib._bootstrap>", line 955, in _find_and_load_unlocked
  File "<frozen importlib._bootstrap>", line 665, in _load_unlocked
  File "<frozen importlib._bootstrap_external>", line 678, in exec_module
  File "<frozen importlib._bootstrap>", line 219, in _call_with_frames_removed
  File "/opt/ralph/ralph-core/lib/python3.6/site-packages/ralph/admin/__init__.py", line 2, in <module>
    from ralph.admin.mixins import (
  File "/opt/ralph/ralph-core/lib/python3.6/site-packages/ralph/admin/mixins.py", line 23, in <module>
    from mptt.admin import MPTTAdminForm, MPTTModelAdmin
  File "/opt/ralph/ralph-core/lib/python3.6/site-packages/mptt/admin.py", line 26, in <module>
    from mptt.models import MPTTModel, TreeForeignKey
  File "/opt/ralph/ralph-core/lib/python3.6/site-packages/mptt/models.py", line 377, in <module>
    class MPTTModel(six.with_metaclass(MPTTModelBase, models.Model)):
  File "/opt/ralph/ralph-core/lib/python3.6/site-packages/django/utils/six.py", line 808, in __new__
    return meta(name, bases, d)
  File "/opt/ralph/ralph-core/lib/python3.6/site-packages/mptt/models.py", line 264, in __new__
    cls = super_new(meta, class_name, bases, class_dict)
  File "/opt/ralph/ralph-core/lib/python3.6/site-packages/django/db/models/base.py", line 139, in __new__
    new_class.add_to_class('_meta', Options(meta, **kwargs))
  File "/opt/ralph/ralph-core/lib/python3.6/site-packages/django/db/models/base.py", line 324, in add_to_class
    value.contribute_to_class(cls, name)
  File "/opt/ralph/ralph-core/lib/python3.6/site-packages/django/db/models/options.py", line 250, in contribute_to_class
    self.db_table = truncate_name(self.db_table, connection.ops.max_name_length())
  File "/opt/ralph/ralph-core/lib/python3.6/site-packages/django/db/__init__.py", line 36, in __getattr__
    return getattr(connections[DEFAULT_DB_ALIAS], item)
  File "/opt/ralph/ralph-core/lib/python3.6/site-packages/django/db/utils.py", line 241, in __getitem__
    backend = load_backend(db['ENGINE'])
  File "/opt/ralph/ralph-core/lib/python3.6/site-packages/django/db/utils.py", line 112, in load_backend
    return import_module('%s.base' % backend_name)
  File "/opt/ralph/ralph-core/lib/python3.6/importlib/__init__.py", line 126, in import_module
    return _bootstrap._gcd_import(name[level:], package, level)
  File "/opt/ralph/ralph-core/lib/python3.6/site-packages/django/db/backends/postgresql_psycopg2/base.py", line 24, in <module>
    raise ImproperlyConfigured("Error loading psycopg2 module: %s" % e)
django.core.exceptions.ImproperlyConfigured: Error loading psycopg2 module: No module named 'psycopg2'

Thanks for you time and attention