Added instructions for how to use ISecrets.cs

.gitignore

@@ -541,3 +541,4 @@ MigrationBackup/
 .ionide/
 
 # End of https://www.toptal.com/developers/gitignore/api/intellij,rider,visualstudio,dotnetcore,windows
+/GoldbergGUI.Core/Utils/Secrets.cs

GoldbergGUI.Core/Utils/ISecrets.cs

@@ -1,3 +1,19 @@
+// Create a "Secrets" class, implement "ISecrets" interface and add your keys:
+/*
+using System;
+
+namespace GoldbergGUI.Core.Utils
+{
+    public class Secrets : ISecrets
+    {
+        public string SteamWebApiKey()
+        {
+            return "<ENTER STEAM WEB API KEY HERE>";
+        }
+    }
+}
+ */
+
 namespace GoldbergGUI.Core.Utils
 {
     public interface ISecrets