pip install django-system-globals

INSTALLED_APPS = (
    ...
    'system_globals',
    ...
)

TEMPLATE_CONTEXT_PROCESSORS = (
    ...
    'system_globals.context_processors.system_globals',
    ...
)

>>> from system_globals.models import SystemGlobal

# setting PI
>>> SystemGlobal.objects.set('MATH_PI', '3.1416')
>>> SystemGlobal.objects.set('MATH_E', ' 2.7182 ')

# retrieving PI
>>> SystemGlobal.objects.get_value('MATH_PI')
3.1416

# retrieving E
>>> SystemGlobal.objects.get_value('MATH_E')
2.7182

# retrieving various system globals
>>> SystemGlobal.objects.as_dict()
{'MATH_PI': 3.1416, 'MATH_E': 2.7182}

>>> SystemGlobal.objects.as_dict(coerce=False)
{'MATH_PI': '3.1416', 'MATH_E': ' 2.7182 '}

>>> SystemGlobal.objects.as_dict(to_lower=True)
{'math_pi': 3.1416, 'math_e': 2.7182}

>>> SystemGlobal.objects.as_dict(prefix='MATH_')
{'PI': 3.1416, 'E': 2.7182}

>>> SystemGlobal.objects.as_dict(prefix='math_')
{'PI': 3.1416, 'E': 2.7182}