Add django constance to thirdpart to void dependency

thirdpart/constance/base.py

@@ -0,0 +1,30 @@
+from . import settings, utils
+
+
+class Config(object):
+    """
+    The global config wrapper that handles the backend.
+    """
+    def __init__(self):
+        super(Config, self).__setattr__('_backend',
+            utils.import_module_attr(settings.BACKEND)())
+
+    def __getattr__(self, key):
+        try:
+            default, help_text = settings.CONFIG[key]
+        except KeyError:
+            raise AttributeError(key)
+        result = self._backend.get(key)
+        if result is None:
+            result = default
+            setattr(self, key, default)
+            return result
+        return result
+
+    def __setattr__(self, key, value):
+        if key not in settings.CONFIG:
+            raise AttributeError(key)
+        self._backend.set(key, value)
+
+    def __dir__(self):
+        return settings.CONFIG.keys()