create project and customercontroller

AB.Services.Abstractions/AB.Services.Abstractions.csproj

@@ -0,0 +1,9 @@
+<Project Sdk="Microsoft.NET.Sdk">
+
+  <PropertyGroup>
+    <TargetFramework>net6.0</TargetFramework>
+    <ImplicitUsings>enable</ImplicitUsings>
+    <Nullable>enable</Nullable>
+  </PropertyGroup>
+
+</Project>

AB.Services.Abstractions/ICustomerService.cs

@@ -0,0 +1,17 @@
+using AB.Contracts;
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+
+namespace AB.Services.Abstractions
+{
+    public interface ICustomerService
+    {
+        Task<CustomerDto> CreateAsync(CustomerForCreationDto customerForCreation);
+        Task DeleteAsync(Guid customerId, CancellationToken cancellationToken);
+        Task<IEnumerable<CustomerDto>> GetAllAsync(CancellationToken cancellationToken);
+        Task<CustomerDto> GetByIdAsync(Guid customerId, CancellationToken cancellationToken);
+    }
+}