Implicit setup can also fail with ImproperlyConfigured.

Fix #511.

Author: aaugustin

docs/conf.py

@@ -265,7 +265,10 @@
 
 
 # Example configuration for intersphinx: refer to the Python standard library.
-intersphinx_mapping = {'http://docs.python.org/': None}
+intersphinx_mapping = {
+    'http://docs.python.org/': None,
+    'http://docs.djangoproject.com/en/dev/': 'http://docs.djangoproject.com/en/dev/_objects/',
+}
 
 # -- Options for Read the Docs --------------------------------------------
 

docs/installation.rst

@@ -55,9 +55,11 @@ what it does, or if you prefer defining your settings explicitly, read below.
 .. warning::
 
     The automatic setup imports your project's URLconf in order to add the
-    Debug Toolbar's URLs. This may trigger circular imports when the URLconf
-    imports views that import models. If you're hitting an :exc:`ImportError`,
-    follow the explicit setup instructions.
+    Debug Toolbar's URLs. This may trigger circular imports, for instance when
+    the URLconf imports views that import models. If the development server
+    crashes with a long stack trace after hitting an :exc:`ImportError` or an
+    :exc:`~django.core.exceptions.ImproperlyConfigured` exception, follow the
+    explicit setup instructions.
 
 Explicit setup
 --------------