Amazon inventory ledger testing and implementation

Tested what I can until more data for the Amazon Ledger Detail table comes in

src/bnhtrade.Core/Logic/Stock/SkuTransactionCrud.cs

@@ -126,9 +126,6 @@ namespace bnhtrade.Core.Logic.Stock
         /// <exception cref="Exception"></exception>
         public int Create(Model.Stock.SkuTransactionCreate skuTransaction)
         {
-            // need to add function to check if transaction type exists, if not, create a new one.
-            throw new NotImplementedException();
-
             if (skuTransaction == null)
             {
                 throw new Exception(err + "Object was null");