CPU profiling (#1371)

* Add cpuprofile flag
* Add notes to readme

main.go

@@ -2,6 +2,11 @@
 package main
 
 import (
+	"os"
+	"os/signal"
+	"runtime/pprof"
+	"syscall"
+
 	"github.com/stashapp/stash/pkg/api"
 	"github.com/stashapp/stash/pkg/manager"
 
@@ -12,9 +17,16 @@ import (
 func main() {
 	manager.Initialize()
 	api.Start()
+
+	// stop any profiling at exit
+	defer pprof.StopCPUProfile()
 	blockForever()
 }
 
 func blockForever() {
-	select {}
+	// handle signals
+	signals := make(chan os.Signal, 1)
+	signal.Notify(signals, syscall.SIGINT, syscall.SIGTERM)
+
+	<-signals
 }