Add support for YAML configuration files. Add support for editing setting options and saving them using the new YAML configuration file support. Add new revertsettings management command. Add new permission to edit setting via the UI.

Signed-off-by: Roberto Rosario <roberto.rosario.gonzalez@gmail.com>

mayan/apps/smart_settings/management/commands/revertsettings.py

@@ -0,0 +1,29 @@
+from __future__ import unicode_literals
+
+import errno
+import os
+from shutil import copyfile
+
+from django.conf import settings
+from django.core import management
+from django.core.management.utils import get_random_secret_key
+
+
+class Command(management.BaseCommand):
+    help = 'Rollback the configuration file to the last valid version.'
+
+    def handle(self, *args, **options):
+        try:
+            copyfile(
+                settings.CONFIGURATION_LAST_GOOD_FILEPATH,
+                settings.CONFIGURATION_FILEPATH
+            )
+        except IOError as exception:
+            if exception.errno == errno.ENOENT:
+                self.stdout.write(
+                    self.style.NOTICE(
+                        'There is no last valid version to restore.'
+                    )
+                )
+            else:
+                raise