Добавьте файлы проекта.

Yuna.Website/Yuna.Website.Server/Storage/Repositories/Device/IDeviceRepository.cs

@@ -0,0 +1,14 @@
+using Yuna.Website.Server.Model;
+
+namespace Yuna.Website.Server.Storage.Repositories.Device
+{
+    public interface IDeviceRepository
+    {
+        public Task<Model.Device> GetById(long id);
+        public Task<IReadOnlyList<Model.Device>> GetList();
+        public Task<Model.Device?> Create(Model.Device device);
+        //public Task<User?> Update(User user);
+        public Task<Model.Device?> Delete(long id);
+        public Task AddProps(IReadOnlyList<Model.Prop> skills, long deviceId);
+    }
+}