nixpkgs/pkgs/development/python-modules/mezzanine/writable_settings.patch

diff -Nur mezzanine-3.1.10/mezzanine/bin/mezzanine_project.py mezzanine-3.1.10-patched/mezzanine/bin/mezzanine_project.py
--- mezzanine-3.1.10/mezzanine/bin/mezzanine_project.py	2014-08-30 07:12:19.000000000 +0200
+++ mezzanine-3.1.10-patched/mezzanine/bin/mezzanine_project.py	2016-10-31 14:47:30.982401818 +0100
@@ -5,6 +5,7 @@
 from distutils.dir_util import copy_tree
 from optparse import OptionParser
 import os
+import stat
 from shutil import move
 from uuid import uuid4
 
@@ -61,6 +62,9 @@
         copy_tree(os.path.join(package_path, "project_template"), project_path)
         move(local_settings_path + ".template", local_settings_path)
 
+    os.chmod(local_settings_path,
+             os.stat(local_settings_path).st_mode | stat.S_IWRITE)
+
     # Generate a unique SECRET_KEY for the project's setttings module.
     with open(local_settings_path, "r") as f:
         data = f.read()