Feature #49: Active Directory Managed Groups

Document Template Attachments, Device Batches, Device Profiles and User
Flags can be associated with an Active Directory group. This AD group is
then automatically synchronized with relevant User/Machine accounts.
Contains various other UI tweaks and configuration enhancements.

Disco.Services/Users/UserFlags/Cache.cs

@@ -42,28 +42,9 @@ namespace Disco.Services.Users.UserFlags
             return _Cache.Values.ToList();
         }
 
-        public UserFlag Update(UserFlag UserFlag)
+        public void AddOrUpdate(UserFlag UserFlag)
         {
-            UserFlag existingItem;
-
-            if (_Cache.TryGetValue(UserFlag.Id, out existingItem))
-            {
-                if (_Cache.TryUpdate(UserFlag.Id, UserFlag, existingItem))
-                {
-                    return UserFlag;
-                }
-                else
-                    return null;
-            }
-            else
-            {
-                if (_Cache.TryAdd(UserFlag.Id, UserFlag))
-                {
-                    return UserFlag;
-                }
-                else
-                    return null;
-            }
+            _Cache.AddOrUpdate(UserFlag.Id, UserFlag, (key, existingItem) => UserFlag);
         }
 
         public UserFlag Remove(int UserFlagId)