Creates the MemberGroupRepository and supporting models.

src/Umbraco.Core/Models/IMemberGroup.cs

@@ -0,0 +1,12 @@
+using Umbraco.Core.Models.EntityBase;
+
+namespace Umbraco.Core.Models
+{
+    /// <summary>
+    /// Represents a member type
+    /// </summary>
+    public interface IMemberGroup : IAggregateRoot
+    {
+        string Name { get; set; }
+    }
+}

src/Umbraco.Core/Models/MemberGroup.cs

@@ -0,0 +1,33 @@
+using System;
+using System.Reflection;
+using System.Runtime.Serialization;
+using Umbraco.Core.Models.EntityBase;
+
+namespace Umbraco.Core.Models
+{
+    /// <summary>
+    /// Represents a member type
+    /// </summary>
+    [Serializable]
+    [DataContract(IsReference = true)]
+    public class MemberGroup : Entity, IMemberGroup
+    {
+        private string _name;
+
+        private static readonly PropertyInfo NameSelector = ExpressionHelper.GetPropertyInfo<MemberGroup, string>(x => x.Name);
+
+        [DataMember]
+        public string Name
+        {
+            get { return _name; }
+            set
+            {
+                SetPropertyValueAndDetectChanges(o =>
+                {
+                    _name = value;
+                    return _name;
+                }, _name, NameSelector);
+            }
+        }
+    }
+}