Add backtest results for SPY for the VIX 5% strategy

strategies/vix-5-percent/README.md

@@ -7,4 +7,12 @@ This swing trading strategy was taken from chapter 5 in *[Short Term Trading Str
 1. If VIX is 5% or more above its 10-day moving average, enter a long position (e.g., on SPY).
 2. Exit the position when VIX is 5% or more below its 10-day moving average.
 
+## Backtest Results
+
+### SPY
+
+![SPY Analysis](./backtest-results/spy_analysis.png)
+
+![SPY Summary](./backtest-results/spy_summary.png)
+
 ---