Fix startup programs for deployment (#29)

Co-authored-by: Maxime Adler <madler@sqli.com>
Reviewed-on: #29

src/GameIdeas/Client/GameIdeas.BlazorApp/Program.cs

@@ -16,10 +16,15 @@ var services = builder.Services;
 builder.RootComponents.Add<App>("#app");
 builder.RootComponents.Add<HeadOutlet>("head::after");
 
+#if DEBUG
 UriBuilder uriBuilder = new(builder.HostEnvironment.BaseAddress)
 {
     Port = 8000
 };
+#else
+UriBuilder uriBuilder = new(Environment.GetEnvironmentVariable("API_URL")
+    ?? throw new ArgumentNullException("API_URL", "Environment variable API_URL is missing"));
+#endif
 
 services.AddHttpClient(
     "GameIdeas.WebAPI",