Migrations refactoring - WIP - move code

src/Umbraco.Core/Migrations/IMigration.cs

@@ -0,0 +1,13 @@
+using Umbraco.Core.Composing;
+
+namespace Umbraco.Core.Migrations
+{
+    /// <summary>
+    /// Marker interface for database migrations
+    /// </summary>
+    public interface IMigration : IDiscoverable
+    {
+        void Up();
+        void Down();
+    }
+}