Added device service. Added API for clearing out token for a device identifier (used for push unregister).

src/Core/Services/DeviceService.cs

@@ -0,0 +1,31 @@
+using System;
+using System.Threading.Tasks;
+using Bit.Core.Domains;
+using Bit.Core.Repositories;
+
+namespace Bit.Core.Services
+{
+    public class DeviceService : IDeviceService
+    {
+        private readonly IDeviceRepository _deviceRepository;
+
+        public DeviceService(
+            IDeviceRepository deviceRepository)
+        {
+            _deviceRepository = deviceRepository;
+        }
+
+        public async Task SaveAsync(Device device)
+        {
+            if(device.Id == default(Guid))
+            {
+                await _deviceRepository.CreateAsync(device);
+            }
+            else
+            {
+                device.RevisionDate = DateTime.UtcNow;
+                await _deviceRepository.ReplaceAsync(device);
+            }
+        }
+    }
+}

src/Core/Services/IDeviceService.cs

@@ -0,0 +1,10 @@
+using System.Threading.Tasks;
+using Bit.Core.Domains;
+
+namespace Bit.Core.Services
+{
+    public interface IDeviceService
+    {
+        Task SaveAsync(Device device);
+    }
+}