Add benchmarking info to README

Style fixes in README.

README.md

@@ -1,5 +1,4 @@
-slug
-====
+# slug
 
 Package `slug` generate slug from unicode string, URL-friendly slugify with
 multiple languages support.
@@ -31,7 +30,7 @@ func main() {
 
 	deText := slug.MakeLang("Diese & Dass", "de")
 	fmt.Println(deText) // Will print: "diese-und-dass"
-	
+
 	slug.Lowercase = false // Keep uppercase characters
 	deUppercaseText := slug.MakeLang("Diese & Dass", "de")
         fmt.Println(deUppercaseText) // Will print: "Diese-und-Dass"
@@ -42,17 +41,30 @@ func main() {
 	textSub := slug.Make("water is hot")
 	fmt.Println(textSub) // Will print: "sand-is-hot"
 }
-
 ```
 
 ### Requests or bugs?
+
 <https://github.com/gosimple/slug/issues>
 
 ## Installation
-```sh
+
+```shell
 go get -u github.com/gosimple/slug
 ```
 
+## Benchmarking
+
+```shell
+go get -u golang.org/x/perf/cmd/benchstat
+
+go test -run=NONE -bench=. ./... > old.txt
+# make changes
+go test -run=NONE -bench=. ./... > new.txt
+
+benchstat old.txt new.txt
+```
+
 ## License
 
 The source files are distributed under the