Update tasks.rst

Makes it so an actual path is added to sys.path.

docs/userguide/tasks.rst

@@ -176,7 +176,7 @@ add the project directory to the Python path::
 
     import os
     import sys
-    sys.path.append(os.path.dirname(os.path.basename(__file__)))
+    sys.path.append(os.path.dirname(os.path.realpath(__file__)))
 
     INSTALLED_APPS = ('myapp', )