Refactoring

The main server owns the migrations, it's the server part,
it's simpler.

It's Yavsc, not one of its lib.

src/Yavsc/Controllers/Contracting/MusicalTendenciesController.cs

@@ -5,6 +5,7 @@ namespace Yavsc.Controllers
     using Models;
     using Models.Musical;
     using Yavsc.Helpers;
+    using Yavsc.Server.Helpers;
 
     public class MusicalTendenciesController : Controller
     {