Ask user what he wants an opinion about if nothing is given

DeukBot4/Utilities/BotOpinions.cs

@@ -9,6 +9,10 @@ namespace DeukBot4.Utilities
         public static async Task<string> GetOpinion(CommandRequest request)
         {
             var extend = request.Parameters[0].AsString().ToLowerInvariant();
+            if (string.IsNullOrWhiteSpace(extend))
+            {
+                return "Think about what?";
+            }
             var random   = new Random(extend.GetHashCode());
             var positive = random.Next(-20, 80) < (int) request.RequestPermissions;