Started implementing backend

App/Program.cs

@@ -1,4 +1,5 @@
 using Microsoft.Extensions.DependencyInjection;
+using Logic;
 
 namespace Keychain;
 
@@ -25,6 +26,7 @@ class Program
     {
         var services = new ServiceCollection();
         //services.AddTransient<IPasswordStoreService, PasswordStoreService>();
+        services.AddSingleton<IPasswordStoreService, PasswordStoreService>();
         return services.BuildServiceProvider();
     }
 }