Made AddAsync method fully asynchronous

src/Infrastructure/Data/EfRepository.cs

@@ -1,6 +1,6 @@
-using Microsoft.eShopWeb.ApplicationCore.Interfaces;
-using Microsoft.EntityFrameworkCore;
+using Microsoft.EntityFrameworkCore;
 using Microsoft.eShopWeb.ApplicationCore.Entities;
+using Microsoft.eShopWeb.ApplicationCore.Interfaces;
 using System.Collections.Generic;
 using System.Linq;
 using System.Threading.Tasks;
@@ -43,7 +43,7 @@ namespace Microsoft.eShopWeb.Infrastructure.Data
 
         public async Task<T> AddAsync(T entity)
         {
-            _dbContext.Set<T>().Add(entity);
+            await _dbContext.Set<T>().AddAsync(entity);
             await _dbContext.SaveChangesAsync();
 
             return entity;