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/Musical/InstrumentsController.cs

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