add architecture skeleton

GymLogAI.Persistence/DesignTimeAppDbContextFactory.cs

@@ -0,0 +1,15 @@
+using Microsoft.EntityFrameworkCore;
+using Microsoft.EntityFrameworkCore.Design;
+
+namespace GymLogAI.Persistence;
+
+public sealed class DesignTimeAppDbContextFactory : IDesignTimeDbContextFactory<AppDbContext>
+{
+    public AppDbContext CreateDbContext(string[] args)
+    {
+        var optionsBuilder = new DbContextOptionsBuilder<AppDbContext>();
+        optionsBuilder.UseNpgsql("Host=localhost;Port=5432;Database=gymlogai;Username=postgres;Password=postgres");
+
+        return new AppDbContext(optionsBuilder.Options);
+    }
+}