WIP - moving tree and section service implementations to Web because they are web based and they need web based objects, there's no sense in coying all of the non-web objects to Core. Now we need to use IoC for the ServiceContext

src/Umbraco.Web/Models/Trees/ApplicationAttribute.cs

@@ -0,0 +1,34 @@
+using System;
+
+namespace Umbraco.Web.Models.Trees
+{
+    /// <summary>
+    /// Identifies an application tree
+    /// </summary>
+    [AttributeUsage(AttributeTargets.Class, AllowMultiple = false)]
+    public class ApplicationAttribute : Attribute
+    {
+        /// <summary>
+        /// Initializes a new instance of the <see cref="ApplicationAttribute"/> class.
+        /// </summary>
+        /// <param name="alias">The alias.</param>
+        /// <param name="name">The name.</param>
+        /// <param name="icon">The icon.</param>
+        /// <param name="sortOrder">The sort order.</param>
+        public ApplicationAttribute(string alias,
+            string name,
+            string icon,
+            int sortOrder = 0)
+        {
+            Alias = alias;
+            Name = name;
+            Icon = icon;
+            SortOrder = sortOrder;
+        }
+
+        public string Alias { get; private set; }
+        public string Name { get; private set; }
+        public string Icon { get; private set; }
+        public int SortOrder { get; private set; }
+    }
+}